USE flag index

---

Global USE flags

Flag	Description
X	Add support for X11
Xaw3d	Add support for the 3d athena widget set
a52	Enable support for decoding ATSC A/52 streams used in DVD
aac	Enable support for MPEG-4 AAC Audio
aalib	Add support for media-libs/aalib (ASCII-Graphics Library)
accessibility	Add support for accessibility (eg 'at-spi' library)
acl	Add support for Access Control Lists
acpi	Add support for Advanced Configuration and Power Interface
adns	Add support for asynchronous DNS resolution
afs	Add OpenAFS support (distributed file system)
alsa	Add support for media-libs/alsa-lib (Advanced Linux Sound Architecture)
ao	Use libao audio output library for sound playback
apache2	Add Apache2 support
aqua	Include support for the Mac OS X Aqua (Carbon/Cocoa) GUI
asm	Enable using assembly for optimization
atm	Enable Asynchronous Transfer Mode protocol support
apparmor	Enable support for the AppArmor application security system
appindicator	Build in support for notifications using the libindicate or libappindicator plugin
audiofile	Add support for libaudiofile where applicable
audit	Enable support for Linux audit subsystem using sys-process/audit
avif	Add AV1 Image Format (AVIF) support
bash-completion	Enable bash-completion support
berkdb	Add support for sys-libs/db (Berkeley DB for MySQL)
bidi	Enable bidirectional language support
big-endian	Big-endian toolchain support
bindist	Flag to enable or disable options for prebuilt (GRP) packages (eg. due to licensing issues)
blas	Add support for the virtual/blas numerical library
bluetooth	Enable Bluetooth Support
branding	Enable Gentoo specific branding
brotli	Enable Brotli compression support
build	!!internal use only!! DO NOT SET THIS FLAG YOURSELF!, used for creating build images and the first half of bootstrapping [make stage1]
bzip2	Enable bzip2 compression support
cairo	Enable support for the cairo graphics library
calendar	Add support for calendars (not using mcal!)
caps	Use Linux capabilities library to control privilege
cdb	Add support for the CDB database engine from the author of qmail
cdda	Add Compact Disk Digital Audio (Standard Audio CD) support
cddb	Access cddb servers to retrieve and submit information about compact disks
cdinstall	Copy files from the CD rather than asking the user to copy them, mostly used with games
cdr	Add support for CD writer hardware
cgi	Add CGI script support
cjk	Add support for Multi-byte character languages (Chinese, Japanese, Korean)
clamav	Add support for Clam AntiVirus software (usually with a plugin)
colord	Support color management using x11-misc/colord
connman	Add support for net-misc/connman
coreaudio	Build the CoreAudio driver on Mac OS X systems
cracklib	Support for cracklib strong password checking
crypt	Add support for encryption -- using mcrypt or gpg where applicable
css	Enable reading of encrypted DVDs
cuda	Enable NVIDIA CUDA support (computation on GPU)
cups	Add support for CUPS (Common Unix Printing System)
curl	Add support for client-side URL transfer library
custom-cflags	Build with user-specified CFLAGS (unsupported)
cvs	Enable CVS (Concurrent Versions System) integration
cxx	Build support for C++ (bindings, extra libraries, code generation, ...)
dbi	Enable dev-db/libdbi (database-independent abstraction layer) support
dbm	Add support for generic DBM databases
dbus	Enable dbus support for anything that needs it (gpsd, gnomemeeting, etc)
debug	Enable extra debug codepaths, like asserts and extra output. If you want to get meaningful backtraces see https://wiki.gentoo.org/wiki/Project:Quality_Assurance/Backtraces
dedicated	Add support for dedicated game servers (some packages do not provide clients and servers at the same time)
dga	Add DGA (Direct Graphic Access) support for X
dist-kernel	Enable subslot rebuilds on Distribution Kernel upgrades
djvu	Support DjVu, a PDF-like document format esp. suited for scanned documents
doc	Add extra documentation (API, Javadoc, etc). It is recommended to enable per package instead of globally
dri	Enable direct rendering: used for accelerated 3D and some 2D, like DMA
dts	Enable DTS Coherent Acoustics decoder support
dv	Enable support for a codec used by many camcorders
dvb	Add support for DVB (Digital Video Broadcasting)
dvd	Add support for DVDs
dvdr	Add support for DVD writer hardware (e.g. in xcdroast)
eds	Enable support for Evolution-Data-Server (EDS)
egl	Enable EGL (Embedded-System Graphics Library, interfacing between windowing system and OpenGL/GLES) support
elogind	Enable session tracking via sys-auth/elogind
emacs	Add support for GNU Emacs
emboss	Add support for the European Molecular Biology Open Software Suite
encode	Add support for encoding of audio or video files
examples	Install examples, usually source code
exif	Add support for reading EXIF headers from JPEG and TIFF images
expat	Enable the use of dev-libs/expat for XML parsing
fam	Enable FAM (File Alteration Monitor) support
fastcgi	Add support for the FastCGI interface
fbcon	Add framebuffer support for the console, via the kernel
ffmpeg	Enable ffmpeg/libav-based audio/video codec support
fftw	Use FFTW library for computing Fourier transforms
filecaps	Use Linux file capabilities to control privilege rather than set*id (this is orthogonal to USE=caps which uses capabilities at runtime e.g. libcap)
firebird	Add support for the Firebird relational database
flac	Add support for FLAC: Free Lossless Audio Codec
fltk	Add support for the Fast Light Toolkit gui interface
fontconfig	Support for configuring and customizing font access via media-libs/fontconfig
fortran	Add support for fortran
freetds	Add support for the TDS protocol to connect to MSSQL/Sybase databases
ftp	Add FTP (File Transfer Protocol) support
gd	Add support for media-libs/gd (to generate graphics on the fly)
gdbm	Add support for sys-libs/gdbm (GNU database libraries)
geoip	Add geoip support for country and city lookup based on IPs
geolocation	Enable physical position determination
ggi	Add support for media-libs/libggi (non-X video api/drivers)
gif	Add GIF image support
gimp	Build a plugin for the GIMP
git	Enable git (version control system) support
gles2	Enable GLES 2.0 (OpenGL for Embedded Systems) support (independently of full OpenGL, see also: gles2-only)
gles2-only	Use GLES 2.0 (OpenGL for Embedded Systems) or later instead of full OpenGL (see also: gles2)
glut	Build an OpenGL plugin using the GLUT library
gmp	Add support for dev-libs/gmp (GNU MP library)
gnome	Add GNOME support
gnome-keyring	Enable support for storing passwords via gnome-keyring
gnuplot	Enable support for gnuplot (data and function plotting)
gnutls	Prefer net-libs/gnutls as SSL/TLS provider (ineffective with USE=-ssl)
gphoto2	Add digital camera support
gpm	Add support for sys-libs/gpm (Console-based mouse driver)
gps	Add support for Global Positioning System
graphicsmagick	Build and link against GraphicsMagick instead of ImageMagick (requires USE=imagemagick if optional)
graphviz	Add support for the Graphviz library
gsl	Use the GNU scientific library for calculations
gsm	Add support for the gsm lossy speech compression codec
gstreamer	Add support for media-libs/gstreamer (Streaming media)
gtk	Add support for x11-libs/gtk+ (The GIMP Toolkit)
gtk-doc	Build and install gtk-doc based developer documentation for dev-util/devhelp, IDE and offline use
gui	Enable support for a graphical user interface
guile	Add support for the guile Scheme interpreter
gzip	Compress files with Lempel-Ziv coding (LZ77)
handbook	Enable handbooks generation for packages by KDE
hardened	Activate default security enhancements for toolchain (gcc, glibc, binutils)
hddtemp	Enable monitoring of hdd temperature (app-admin/hddtemp)
hdf5	Add support for the Hierarchical Data Format v5
headers-only	Install only C headers instead of whole package. Mainly used by sys-devel/crossdev for toolchain bootstrap.
heif	Enable support for ISO/IEC 23008-12:2017 HEIF/HEIC image format
hscolour	Include coloured haskell sources to generated documentation (dev-haskell/hscolour)
http2	Enable support for the HTTP/2 protocol
ibm	Add support for IBM ppc64 specific systems
iconv	Enable support for the iconv character set conversion library
icu	Enable ICU (Internationalization Components for Unicode) support, using dev-libs/icu
idn	Enable support for Internationalized Domain Names
ieee1394	Enable FireWire/iLink IEEE1394 support (dv, camera, ...)
imagemagick	Enable optional support for the ImageMagick or GraphicsMagick image converter
imap	Add support for IMAP (Internet Mail Application Protocol)
imlib	Add support for imlib, an image loading and rendering library
infiniband	Enable Infiniband RDMA transport support
initramfs	Include kernel modules in the initramfs, and re-install the kernel (only effective for distribution kernels)
inotify	Enable inotify filesystem monitoring support
introspection	Add support for GObject based introspection
iodbc	Add support for iODBC library
ios	Enable support for Apple's iDevice with iOS operating system (iPad, iPhone, iPod, etc)
ipod	Enable support for iPod device access
ipv6	Add support for IP version 6
jack	Add support for the JACK Audio Connection Kit
java	Add support for Java
javascript	Enable javascript support
jbig	Enable jbig-kit support for tiff, Hylafax, ImageMagick, etc
jemalloc	Use dev-libs/jemalloc for memory management
jit	Enable just-in-time compilation for improved performance. May prevent use of some PaX memory protection features in Gentoo Hardened.
joystick	Add support for joysticks in all packages
jpeg	Add JPEG image support
jpeg2k	Support for JPEG 2000, a wavelet-based image compression format
jpegxl	Add JPEG XL image support
kde	Add support for software made by KDE, a free software community
kerberos	Add kerberos support
keyring	Enable support for freedesktop.org Secret Service API password store
ladspa	Enable the ability to support ladspa plugins
lame	Prefer using LAME libraries for MP3 encoding support
lapack	Add support for the virtual/lapack numerical library
lash	Add LASH Audio Session Handler support
latex	Add support for LaTeX (typesetting package)
lcms	Add lcms support (color management engine)
ldap	Add LDAP support (Lightweight Directory Access Protocol)
lerc	Add LERC suppport (Limited Error Raster Compression)
libass	SRT/SSA/ASS (SubRip / SubStation Alpha) subtitle support
libcaca	Add support for colored ASCII-art graphics
libedit	Use the libedit library (replacement for readline)
libffi	Enable support for Foreign Function Interface library
libnotify	Enable desktop notification support
libsamplerate	Build with support for converting sample rates using libsamplerate
libwww	Add libwww support (General purpose WEB API)
lirc	Add support for lirc (Linux's Infra-Red Remote Control)
livecd	!!internal use only!! DO NOT SET THIS FLAG YOURSELF!, used during livecd building
llvm-libunwind	Use sys-libs/llvm-libunwind instead of sys-libs/libunwind
lm-sensors	Add linux lm-sensors (hardware sensors) support
lto	Enable Link-Time Optimization (LTO) to optimize the build
lua	Enable Lua scripting support
lz4	Enable support for lz4 compression (as implemented in app-arch/lz4)
lzip	Enable support for lzip compression
lzma	Support for LZMA compression algorithm
lzo	Enable support for lzo compression
m17n-lib	Enable m17n-lib support
mad	Add support for mad (high-quality mp3 decoder library and cli frontend)
magic	Add support for file type detection via magic bytes (usually via libmagic from sys-apps/file)
maildir	Add support for maildir (~/.maildir) style mail spools
man	Build and install man pages
matroska	Add support for the matroska container format (extensions .mkv, .mka and .mks)
mbox	Add support for mbox (/var/spool/mail) style mail spools
memcached	Add support for memcached
mhash	Add support for the mhash library
mikmod	Add libmikmod support to allow playing of SoundTracker-style music files
milter	Add sendmail mail filter (milter) support
minimal	Install a very minimal build (disables, for example, plugins, fonts, most drivers, non-critical features)
mmap	Add mmap (memory map) support
mms	Support for Microsoft Media Server (MMS) streams
mng	Add support for libmng (MNG images)
modplug	Add libmodplug support for playing SoundTracker-style music files
modules	Build the kernel modules
modules-compress	Install compressed kernel modules (if kernel config enables module compression)
modules-sign	Cryptographically sign installed kernel modules (requires CONFIG_MODULE_SIG=y in the kernel)
mono	Build Mono bindings to support dotnet type stuff
motif	Add support for the Motif toolkit
mp3	Add support for reading mp3 files
mp4	Support for MP4 container format
mpeg	Add libmpeg3 support to various packages
mpi	Add MPI (Message Passing Interface) layer to the apps that support it
mplayer	Enable mplayer support for playback or encoding
mssql	Add support for Microsoft SQL Server database
mtp	Enable support for Media Transfer Protocol
multilib	On 64bit systems, if you want to be able to compile 32bit and 64bit binaries
musepack	Enable support for the musepack audio codec
musicbrainz	Lookup audio metadata using MusicBrainz community service (musicbrainz.org)
mysql	Add mySQL Database support
mysqli	Add support for the improved mySQL libraries
nas	Add support for network audio sound
native-extensions	Build native (e.g. C, Rust) extensions in addition to pure (e.g. Python) code (usually speedups)
ncurses	Add ncurses support (console display library)
neXt	Enable neXt toolkit
netcdf	Enable NetCDF data format support
networkmanager	Enable net-misc/networkmanager support
nis	Support for NIS/YP services
nls	Add Native Language Support (using gettext - GNU locale utilities)
nntp	Add support for newsgroups (Network News Transfer Protocol)
nocd	Install all files required to run the application without a CD mounted
nsplugin	Build plugin for browsers supporting the Netscape plugin architecture (that is almost any modern browser)
nvenc	Add support for NVIDIA Encoder/Decoder (NVENC/NVDEC) API for hardware accelerated encoding and decoding on NVIDIA cards (requires x11-drivers/nvidia-drivers)
ocaml	Add support/bindings for the Ocaml language
ocamlopt	Enable ocamlopt support (ocaml native code compiler) -- Produces faster programs (Warning: you have to disable/enable it at a global scale)
oci8	Add Oracle 8 Database Support
oci8-instant-client	Use dev-db/oracle-instantclient-basic as Oracle provider instead of requiring a full Oracle server install
odbc	Add ODBC Support (Open DataBase Connectivity)
offensive	Enable potentially offensive items in packages
ofx	Enable support for importing (and exporting) OFX (Open Financial eXchange) data files
ogg	Add support for the Ogg container format (commonly used by Vorbis, Theora and flac)
openal	Add support for the Open Audio Library
opencl	Enable OpenCL support (computation on GPU)
openexr	Support for the OpenEXR graphics file format
opengl	Add support for OpenGL (3D graphics)
openmp	Build support for the OpenMP (support parallel computing), requires >=sys-devel/gcc-4.2 built with USE="openmp"
opentype-compat	Convert BDF and PCF bitmap fonts to OTB wrapper format
opus	Enable Opus audio codec support
oracle	Enable Oracle Database support
orc	Use dev-lang/orc for just-in-time optimization of array operations
osc	Enable support for Open Sound Control
oss	Add support for OSS (Open Sound System)
otf	Install OpenType font versions
pam	Add support for PAM (Pluggable Authentication Modules) - DANGEROUS to arbitrarily flip
pch	Enable precompiled header support for faster compilation at the expense of disk space and memory
pcmcia	Add support for PCMCIA slots/devices found on laptop computers
pcre	Add support for Perl Compatible Regular Expressions
pda	Add support for portable devices
pdf	Add general support for PDF (Portable Document Format), this replaces the pdflib and cpdflib flags
perl	Add optional support/bindings for the Perl language
php	Include support for the PHP language
pie	Build programs as Position Independent Executables (a security hardening technique)
plasma	Build optional KDE plasma addons
plotutils	Add support for plotutils (library for 2-D vector graphics)
png	Add support for libpng (PNG images)
policykit	Enable PolicyKit (polkit) authentication support
portaudio	Add support for the crossplatform portaudio audio API
posix	Add support for POSIX-compatible functions
postgres	Add support for the postgresql database
postscript	Enable support for the PostScript language (often with ghostscript-gpl or libspectre)
ppds	Add support for automatically generated ppd (printing driver) files
prefix	Defines if a Gentoo Prefix offset installation is used
profile	Add support for software performance analysis (will likely vary from ebuild to ebuild)
pulseaudio	Add sound server support via media-libs/libpulse (may be PulseAudio or PipeWire)
python	Add optional support/bindings for the Python language
qdbm	Add support for the qdbm (Quick Database Manager) library
qmail-spp	Add support for qmail SMTP plugins
qt5	Add support for the Qt 5 application and UI framework
qt6	Add support for the Qt 6 application and UI framework
quicktime	Add support for OpenQuickTime
radius	Add support for RADIUS authentication
raw	Add support for raw image formats
rdp	Enables RDP/Remote Desktop support
readline	Enable support for libreadline, a GNU line-editing library that almost everyone wants
recode	Enable support for the GNU recode library
rss	Enable support for RSS feeds
ruby	Add support/bindings for the Ruby language
samba	Add support for SAMBA (Windows File and Printer sharing)
sasl	Add support for the Simple Authentication and Security Layer
savedconfig	Use this to restore your config from /etc/portage/savedconfig ${CATEGORY}/${PN}. Make sure your USE flags allow for appropriate dependencies
scanner	Add support for scanner hardware (e.g. build the sane frontend in kdegraphics)
screencast	Enable support for remote desktop and screen cast using PipeWire
sctp	Support for Stream Control Transmission Protocol
sdl	Add support for Simple Direct Layer (media library)
seccomp	Enable seccomp (secure computing mode) to perform system call filtering at runtime to increase security of programs
secureboot	Automatically sign efi executables using user specified key
selinux	!!internal use only!! Security Enhanced Linux support, this must be set by the selinux profile or breakage will occur
semantic-desktop	Cross-KDE support for semantic search and information retrieval
session	Add persistent session support
sid	Enable SID (Commodore 64 audio) file support
skey	Enable S/Key (Single use password) authentication support
slang	Add support for the slang text display library (it's like ncurses, but different)
smartcard	Enable smartcard support
smp	Enable support for multiprocessors or multicore systems
snappy	Enable support for Snappy compression (as implemented in app-arch/snappy)
sndfile	Add support for libsndfile
snmp	Add support for the Simple Network Management Protocol if available
soap	Add support for SOAP (Simple Object Access Protocol)
sockets	Add support for tcp/ip sockets
socks5	Add support for the socks5 proxy
sound	Enable sound support
source	Zip the sources and install them
sox	Add support for Sound eXchange (SoX)
speech	Enable text-to-speech support
speex	Add support for the speex audio codec (used for speech)
spell	Add dictionary support
split-usr	Enable behavior to support maintaining /bin, /lib*, /sbin and /usr/sbin separately from /usr/bin and /usr/lib*
sqlite	Add support for sqlite - embedded sql database
ssl	Add support for SSL/TLS connections (Secure Socket Layer / Transport Layer Security)
startup-notification	Enable application startup event feedback mechanism
static	!!do not set this during bootstrap!! Causes binaries to be statically linked instead of dynamically
static-libs	Build static versions of dynamic libraries as well
strip	Allow symbol stripping to be performed by the ebuild for special files
subversion	Enable subversion (version control system) support
suid	Enable setuid root program(s)
svg	Add support for SVG (Scalable Vector Graphics)
svga	Add support for SVGAlib (graphics library)
symlink	Force kernel ebuilds to automatically update the /usr/src/linux symlink
syslog	Enable support for syslog
systemd	Enable use of systemd-specific libraries and features like socket activation or session tracking
szip	Use the szip compression library
taglib	Enable tagging support with taglib
tcl	Add support the Tcl language
tcmalloc	Use the dev-util/google-perftools libraries to replace the malloc() implementation with a possibly faster one
tcpd	Add support for TCP wrappers
telemetry	Send anonymized usage information to upstream so they can better understand our users
test	Enable dependencies and/or preparations necessary to run tests (usually controlled by FEATURES=test but can be toggled independently)
test-rust	Enable important test dependencies that require Rust toolchain
theora	Add support for the Theora Video Compression Codec
threads	Add threads support for various packages. Usually pthreads
tidy	Add support for HTML Tidy
tiff	Add support for the TIFF image format
time64	Use 64-bit time_t type instead of the regular 32-bit type. This flag is forced on time64 profiles, and masked elsewhere. It should be only used when detection of type width is not possible (e.g. for SRC_URI)
timidity	Build with Timidity++ (MIDI sequencer) support
tk	Add support for Tk GUI toolkit
truetype	Add support for FreeType and/or FreeType2 fonts
ttf	Install TrueType font versions
udev	Enable virtual/udev integration (device discovery, power and storage device support, etc)
udisks	Enable storage management support (automounting, volume monitoring, etc)
uefi	Enable support for the Unified Extensible Firmware Interface
unicode	Add support for Unicode
unwind	Add support for call stack unwinding and function name resolution
upnp	Enable UPnP port mapping support
upnp-av	Enable UPnP audio/video streaming support
upower	Enable power management support
usb	Add USB support to applications that have optional USB support (e.g. cups)
v4l	Enable support for video4linux (using linux-headers or userspace libv4l libraries)
vaapi	Enable Video Acceleration API for hardware decoding
vala	Enable bindings for dev-lang/vala
valgrind	Enable annotations for accuracy. May slow down runtime slightly. Safe to use even if not currently using dev-debug/valgrind
vanilla	Do not add extra patches which change default behaviour; DO NOT USE THIS ON A GLOBAL SCALE as the severity of the meaning changes drastically
vcd	Video CD support
vdpau	Enable the Video Decode and Presentation API for Unix acceleration interface
verify-sig	Verify upstream signatures on distfiles
vhosts	Add support for installing web-based applications into a virtual-hosting environment
videos	Install optional video files (used in some games)
vim-syntax	Pulls in related vim syntax scripts
vnc	Enable VNC (remote desktop viewer) support
vorbis	Add support for the OggVorbis audio codec
vulkan	Add support for 3D graphics and computing via the Vulkan cross-platform API
wavpack	Add support for wavpack audio compression tools
wayland	Enable dev-libs/wayland backend
webkit	Add support for the WebKit HTML rendering/layout engine
webp	Add support for the WebP image format
wifi	Enable wireless network functions
wmf	Add support for the Windows Metafile vector image format
wxwidgets	Add support for wxWidgets/wxGTK GUI toolkit
x264	Enable h264 encoding using x264
xattr	Add support for extended attributes (filesystem-stored metadata)
xcb	Support the X C-language Binding, a replacement for Xlib
xcomposite	Enable support for the Xorg composite extension
xemacs	Add support for XEmacs
xface	Add xface support used to allow a small image of xface format to be included in an email via the header 'X-Face'
xft	Build with support for XFT font renderer (x11-libs/libXft)
xine	Add support for the XINE movie libraries
xinerama	Add support for querying multi-monitor screen geometry through the Xinerama API
xinetd	Add support for the xinetd super-server
xml	Add support for XML files
xmlrpc	Support for xml-rpc library
xmp	Enable support for Extensible Metadata Platform (Adobe XMP)
xmpp	Enable support for Extensible Messaging and Presence Protocol (XMPP) formerly known as Jabber
xosd	Sends display using the X On Screen Display library
xpm	Add support for XPM graphics format
xscreensaver	Add support for XScreenSaver extension
xv	Add in optional support for the Xvideo extension (an X API for video playback)
xvid	Add support for xvid.org's open-source mpeg-4 codec
zeroconf	Support for DNS Service Discovery (DNS-SD)
zip	Enable support for ZIP archives
zlib	Add support for zlib compression
zsh-completion	Enable zsh completion support
zstd	Enable support for ZSTD compression

Local USE flags

acct-user

git

gitea	Set home directory for git hosting via www-apps/gitea.
gitolite	Set home directory for git hosting via dev-vcs/gitolite or dev-vcs/gitolite-gentoo.

vdr

graphlcd	Prepare group membership for media-plugins/vdr-graphlcd.
legacy-homedir	Keep old home directory /var/vdr of an existing installation. When this useflag is cleared, the home directory is switched to FHS conformant /var/lib/vdr
remote	Prepare group membership for media-plugins/vdr-remote.
serial	Prepare group membership for media-plugins/vdr-serial.

app-accessibility

at-spi2-core

dbus-broker	Use DBus broker implementation instead of default DBus daemon

brltty

api	build brltty's application program interface
beeper	support the console tone generator
fm	support for the sound card synthesizer
louis	Use braille translator dev-libs/liblouis
midi	support the musical instrument digital interface
pcm	support for sound card digital audio

emacspeak

espeak	Adds support for the espeak tts engine

espeak-ng

async	Enables asynchronous commands
klatt	Enables Klatt formant synthesis and implementation
l10n_ru	Builds extended Russian Dictionary file
l10n_zh	Builds extended Chinese (Mandarin and Cantonese) Dictionary files
man	Builds and installs manpage with app-text/ronn-ng
mbrola	Adds support for mbrola voices

flite

voices	Install synthetic voices

freetts

jsapi	build Java Speech API (JSAPI)
mbrola	Adds support for mbrola voices

orca

braille	Enable braille support

speech-dispatcher

espeak	Adds support for espeak-ng speech engine
flite	Adds support for flite speech engine

app-admin

clsync

apidoc	Provide doxygen generated API docs.
cgroups	Use cgroups to limit /dev access.
clsync	Build clsync binary. Most likely you want it. However it is possible to build only libclsync without clsync itself.
cluster	Enable clustering support (allows master-master clsync on multiple hosts). Not fully implemented yet.
control-socket	Enable AF_UNIX control socket support.
extra-debug	Enable extra debugging. This will hurt performance badly. Be ready for tons of output.
extra-hardened	Enable extra security checks. This will hurt performance.
gio	Enable GIO for FS monitoring (glib based alternative to inotify interface, not recommended; if both are compiled, may be selected at runtime).
highload-locks	Allows to use spinlocks for short delays instead of mutexes, but only on SMP systems.
namespaces	Enable namespaces isolation.
socket-library	Build the control and monitoring socket library: libclsync.

conky

apcupsd	Enable support for sys-power/apcupsd
bundled-toluapp	Enable support for bundled toluapp. This only makes sense in combination with the lua-* flags
cmus	Enable monitoring of music played by media-sound/cmus
colour-name-map	Include mappings of colour name
extras	Enable syntax highlighting for app-editors/nanoand app-editors/vim
ical	Enable support for events from iCalendar (RFC 5545) files using dev-libs/libical
intel-backlight	Enable support for Intel backlight
iostats	Enable support for per-task I/O statistics
irc	Enable support for displaying everything from an irc channel using net-libs/libircclient
lua-cairo	Enable if you want Lua Cairo bindings
lua-cairo-xlib	Enable support for Cairo and Xlib interoperability for Lua
lua-imlib	Enable if you want Lua Imlib2 bindings
lua-rsvg	Enable if you want Lua RSVG bindings
math	Enable support for glibc's libm math library
moc	Enable monitoring of music played by media-sound/moc
mouse-events	Enable support for mouse events"
mpd	Enable monitoring of music controlled by media-sound/mpd
nvidia	Enable reading of nvidia card temperature sensors via x11-drivers/nvidia-drivers
portmon	Enable support for tcp (ip4) port monitoring
thinkpad	Enable support for IBM/Lenovo notebooks
webserver	Enable support to act as a webserver serving conkys output using net-libs/libmicrohttpd
xinput	Enable support for Xinput 2 (slow)
xmms2	Enable monitoring of music played by media-sound/xmms2

conserver

freeipmi	Compile in FreeIPMI support via sys-libs/freeipmi

diradm

automount	Support for automount data in LDAP
irixpasswd	Support for storing separate IRIX passwords

doas

persist	Adds support for "persist" feature (experimental)

gkrellm

X	Build both the X11 gui (gkrellm) and the server (gkrellmd). Disabling this flag builds the server only
gnutls	Enable SSL support for mail checking with net-libs/gnutls (overrides 'ssl' USE flag)
lm-sensors	Enable monitoring sensors via sys-apps/lm-sensors
ntlm	Enable NTLM authentication for mail checking with net-libs/libntlm
ssl	Enable SSL support for mail checking with dev-libs/openssl

gtkdiskfree

gtk2	Support GTK+ 2.x instead of GTK+ 3.x

hddtemp

network-cron	Monthly cronjob to update hddtemp.db.

keepass

aot	Generate native code at build time, rather than runtime.

keepassxc

autotype	Add support to autotype the passwords into other applications
browser	Enables browser plugin support
keeshare	Enable KeeShare sharing integration
keyring	Enable support for use as the the system keyring
network	Enable network support
ssh-agent	Use KeePassXC to unlock SSH keys
yubikey	Enable database unlocking via hardware keys supporting YubiKey-style HMAC-SHA1 protocol

lnav

pcap	Enable support for pcap files.

logcheck

cron	Adds file to enable hourly cron job to run logcheck"

logrotate

acl	Installs acl support
cron	Installs cron file
selinux	Installs Security Enhanced Linux support

logstash-bin

x-pack	Enable additional features (may need a license)

openrc-settingsd

systemd	Use the versions of dbus and polkit files provided by sys-apps/systemd

pass

X	Use x11-misc/xclip to copy passwords to the clipboard.
dmenu	Add support for x11-misc/dmenu with the 'passmenu' program.
git	Use dev-vcs/git for password revisions.
importers	Allow importing passwords from other password managers using various contributed scripts.

pass-otp

qrcode	Add support for qrcodes using media-gfx/qrencode

passwordsafe

qr	Enable QR code password display
xml	Enable XML import support
yubikey	Enable support for Yubikey

perl-cleaner

pkgcore	Use sys-apps/pkgcore instead of sys-apps/portage and app-portage/portage-utils.

puppet

augeas	Enable augeas support
diff	Enable diff support
hiera	Enable hiera support
rrdtool	Enable rrdtool support
shadow	Enable shadow support

puppet-agent

puppetdb	Adds puppetdb support

puppetserver

puppetdb	Adds support for connecting to puppetdb

pwgen

livecd	Install init script for root password scrambling on boot

rsyslog

clickhouse	Build the ClickHouse output module (requires net-misc/curl)
curl	Enable http_request() function in RainerScript (requires net-misc/curl)
dbi	Build the general database output module (requires dev-db/libdbi)
elasticsearch	Build the Elasticsearch output module (requires net-misc/curl)
gcrypt	Add support for encrypted log files using dev-libs/libgcrypt
gnutls	Build the GnuTLS network stream driver (requires net-libs/gnutls)
imhttp	Build the http input module (requires www-servers/civetweb)
impcap	Build the pcap input module (requires net-libs/libpcap)
kafka	Build the Apache Kafka input/output module (requires dev-libs/librdkafka)
kerberos	Build the GSSAPI input and output module (requires virtual/krb5)
kubernetes	Build the kubernetes modify plugin (requires net-misc/curl)
mdblookup	Build the MaxMind DB lookup message modify plugin using dev-libs/libmaxminddb
mongodb	Build the MongoDB output module (requires dev-libs/mongo-c-driver)
mysql	Build the MySQL database output module (requires virtual/mysql)
normalize	Build the normalize modify module (requires dev-libs/libee and dev-libs/liblognorm)
omhttp	Build the http output module (requires net-misc/curl)
omhttpfs	Build the httpfs output module (requires net-misc/curl)
omudpspoof	Build the udpspoof output module (requires net-libs/libnet)
openssl	Build the OpenSSL network stream driver (requires dev-libs/openssl)
postgres	Build the PostgreSQL database output module (requires dev-db/postgresql)
rabbitmq	Build the RabbitMQ output module (requires net-libs/rabbitmq-c)
redis	Build the Redis output module using (requires dev-libs/hiredis)
relp	Build the Reliable Event Logging Protocol (RELP) output module (requires dev-libs/librelp)
rfc3195	Build the rfc3195 input module (requires dev-libs/liblogging)
rfc5424hmac	Build the rfc5424hmac modify module (requires dev-libs/openssl)
snmp	Build the snmp modify and output module (requires net-analyzer/net-snmp)
ssl	Add support for encrypted client/server communication (requires net-libs/gnutls)
systemd	Build the journal input and output module (requires sys-apps/systemd)
usertools	Installs the user tools (rsgtutil, rscryutil...) corresponding to the set USE flags
uuid	Include UUIDs in messages (requires sys-apps/util-linux)
xxhash	Enable xxHash support in fmhash module (requires dev-libs/xxhash)
zeromq	Build the ZeroMQ input and output modules (requires net-libs/czmq)

sagan

libdnet	Add support for dev-libs/libdnet
pcap	Add support for network packet capture via net-libs/libpcap
redis	Add support for the Redis database via dev-libs/hiredis
smtp	Build witch SMTP (E-Mail) support

salt

cheetah	Enable support for dev-python/cheetah3
cherrypy	Enable support for using cherrypy.
genshi	Enable support for dev-python/genshi
gnupg	Enable support for gnupg via python-gnupg.
libcloud	Enable salt-cloud support via libcloud.
libvirt	Support managing virtual machines with app-emulation/libvirt.
mako	Add support for using the mako template engine for parsing salt states.
mongodb	Support returning data to a mongodb server.
neutron	Support the OpenStack neutron network service.
nova	Enable support for the OpenStack Nova API
openssl	Add support for using TLS via OpenSSL.
portage	Add support for package state enforcement using sys-apps/portage
raet	Add support for the new RAET transport.
redis	Support returning data to a redis database.
zeromq	Add support for the zeromq transport.

sudo

gcrypt	Use message digest functions from dev-libs/libgcrypt instead of sudo's
offensive	Let sudo print insults when the user types the wrong password
secure-path	Replace PATH variable with compile time secure paths
sendmail	Allow sudo to send emails with sendmail
sssd	Add System Security Services Daemon support

sysklogd

logger	Build the logger program
logrotate	use app-admin/logrotate for rotating logs rather than custom cron scripts

syslog-ng

amqp	Enable support for AMQP destinations
geoip2	Add support for geo lookup based on IPs via dev-libs/libmaxminddb
grpc	Enable GRPC based driver support (OpenTelemetry) via net-libs/grpc
http	Enable support for HTTP destinations
json	Enable support for JSON template formatting via dev-libs/json-c
kafka	Enable support for Kafka destinations
mongodb	Enable support for mongodb destinations
mqtt	Enable MQTT support via net-libs/paho-mqtt-c
pacct	Enable support for reading Process Accounting files (EXPERIMENTAL, Linux only)
redis	Enable support for Redis destinations
smtp	Enable support for SMTP destinations
spoof-source	Enable support for spoofed source addresses

sysstat

dcron	Adjust cronjobs to work properly under sys-process/dcron

testdisk

ewf	Include ewf library
ntfs	Include the ability to read NTFS filesystems
reiserfs	Include reiserfs reading ability
sudo	Enable sudo helper integration

tripwire

ssl	Adds support for Secure Socket Layer connections
static	Builds the package statically
tools	Installs app-admin/mktwpol, providing scripts for the installation/setup of tripwire, including generating the tripwire policy file and maintenance of the tripwire database

ulogd

json	Build JSON output plugin to save packets in JSON file format
nfacct	Build NFACCT input plugin to support traffic accounting via nfnetlink_acct
nfct	Build NFCT input plugin to support stateful flow-based logging via nfnetlink_conntrack
nflog	Build NFLOG input plugin to support stateless packet-based logging via nfnetlink_log
pcap	Build PCAP output plugin to save packets in libpcap file format
ulog	Build ULOG input plugin to support deprecated packet-based logging via ULOG target

vault

webui	Enable the Web UI

webalizer

xtended	Include the 404 extension

webapp-config

portage	Propagate python_targets dependencies to sys-apps/portage

app-alternatives

awk

busybox	Symlink to sys-apps/busybox
gawk	Symlink to sys-apps/gawk
mawk	Symlink to sys-apps/mawk (warning: mawk is not fully POSIX-compliant)
nawk	Symlink to sys-apps/nawk

bc

gh	Symlink to bc-gh from sci-calculators/bc-gh
gnu	Symlink to GNU bc (sys-devel/bc)

bzip2

lbzip2	Symlink to app-arch/lbzip2.
pbzip2	Symlink to app-arch/pbzip2.
reference	Symlink to app-arch/bzip2.

cpio

gnu	Symlink to GNU cpio (app-arch/cpio)
libarchive	Symlink to bsdcpio from app-arch/libarchive

gzip

pigz	Symlink to app-arch/pigz.
reference	Symlink to app-arch/gzip.

lex

flex	Symlink to sys-devel/flex.
reflex	Symlink to sys-devel/reflex.

ninja

reference	Symlink to dev-build/ninja.
samurai	Symlink to dev-build/samurai.

sh

bash	Symlink to app-shells/bash
busybox	Symlink to sys-apps/busybox
dash	Symlink to app-shells/dash
ksh	Symlink to app-shells/ksh
lksh	Symlink to lksh from app-shells/mksh
mksh	Symlink to mksh from app-shells/mksh

tar

gnu	Symlink to GNU tar (app-arch/tar)
libarchive	Symlink to bsdtar from app-arch/libarchive

yacc

bison	Symlink to app-alternatives/yacc.
byacc	Symlink to dev-util/byacc.
reference	Symlink to dev-util/yacc.

app-antivirus

clamav

clamapp	Build applications (clamscan, clamd, clamdscan, clamonacc (also has its own USE flag), sigtool, clambc, clamav-milter (also requires milter USE flag), clamdtop, clamsubmit, clamconf).
clamdtop	A Top like tool which shows what clamd is currently scanning amongst other things
clamonacc	Build the clamonacc on-access scanner
clamsubmit	A tool to submit false positives / negatives
experimental	Enable experimental features
libclamav-only	Bypass building of libfreshclam and the ClamAV CLI applications.
metadata-analysis-api	Enables collection of file property metadata using ClamAV API for analysis by ClamAV bytecode programs.
rar	RAR support
system-mspack	Use dev-libs/libmspack instead of the version bundled with ClamAV
xml	DMG and XAR support

clamtk

kde	Install the Dolphin plugin.
nautilus	Install the Nautilus plugin.
nemo	Install the Nemo plugin.
thunar	Install the Thunar plugin.

app-arch

7zip

jwasm	Use dev-lang/jwasm to include optimized code (doesn't support AES)
rar	Enable support for non-free rar decoder
uasm	Use dev-lang/uasm to include optimized code

cabextract

extras	Install experimental extra tools: wince_info and wince_rename for examining and processing Windows CE installation cabinet header files; cabinfo for examining the structure of a cab file.

createrepo_c

legacy	Build with support for legacy weakdeps and hashes (not recommended!)

dpkg

libmd	Use app-crypt/libmd library for message digest functions
update-alternatives	Install update-alternatives

dump

ermt	encrypted rmt support
uuid	Enable UUID support

engrampa

caja	Enable engrampa to integrate with mate-base/caja by providing entries in its context menu

file-roller

nautilus	Build contextual menu extension for gnome-base/nautilus.

gzip

pic	disable optimized assembly code that is not PIC friendly

innoextract

debug	Enable debug logging and the --debug command-line option
lzma	Enable support for extracting lzma-compressed installers using app-arch/xz-utils

libarchive

blake2	Enable Blake2 hash support via app-crypt/libb2.
bzip2	Allow accessing bzip2-compressed archives through libbz2 (which comes with app-arch/bzip2). This only affects libarchive's native support: bsdtar will keep using bunzip2 as a filter if that's not built-in.
e2fsprogs	Use file flags from sys-fs/e2fsprogs headers instead of virtual/os-headers headers
nettle	Use dev-libs/nettle as crypto backend

libdeflate

test	Build the test programs (requires sys-libs/zlib)
utils	Build the libdeflate-gzip program

lrzip-next

largefile	Enables support for large files
year2038	Enables support for 64-bit 'time_t' (sets D_TIME_BITS=64; glibc only)

p7zip

natspec	Use dev-libs/libnatspec to correctly decode non-ascii file names archived in Windows.
rar	Enable support for non-free rar decoder

rar

all-sfx	Install all SFX (Self-Extracting) files rather than just the native format (allows creation of Windows EXEs on Linux ELF systems)

rpm

sequoia	Use app-crypt/rpm-sequoia instead of the deprecated internal parser

tar

minimal	just install `tar`

unzip

natspec	Use dev-libs/libnatspec to correctly decode non-ascii file names archived in Windows.

wimlib

fuse	Use fuse libraries
iso	Install app-cdr/cdrtools in order to prepare iso images
ntfs	Use libntfs-3g library from sys-fs/ntfs3g
yasm	Use yasm assembler instead of nasm

xz-utils

extra-filters	Build additional filters that are not used in any of the default xz presets. This includes delta and BCJ coders, additional match finders and SHA256 checks.
pgo	Optimize the build using Profile Guided Optimization (PGO)

zip

natspec	Use dev-libs/libnatspec to correctly decode non-ascii file names archived in Windows.

app-backup

amanda

ndmp	Support for the NDMP protocol
s3	Support for backing up to the Amazon S3 system
xfs	Support for backing up raw XFS filesystems using xfsdump

backup-manager

s3	Support for backing up to the Amazon S3 system

bacula

bacula-clientonly	Disable DB support, and just build a client
bacula-nodir	Disable building of director
bacula-nosd	Disable building of storage daemon
batch-insert	Enable batch insert into data base
ipv6	Support IPV6 protocol"
logwatch	Install support files for logwatch

bareos

ceph	Enable sys-cluster/ceph support
clientonly	Only install file-daemon (client)
director	Install director
glusterfs	Enable sys-cluster/glusterfs storage backend
lmdb	enable build of dev-db/lmdb support for faster accurate backup
logwatch	Install support files for sys-apps/logwatch
ndmp	Enable support for NDMP (Network Data Management Protocol)
scsi-crypto	Enable low level SCSI crypto support
storage-daemon	Install storage daemon (bareos-sd)
vmware	Enable bareos-fd VMware plugin

borgmatic

apprise	Allow backup monitoring to send notification to a wide variety of services, using dev-python/apprise

btrbk

lsbtr	Enable the lsbtr command-line tool
mbuffer	Use sys-block/mbuffer to enable progress bar and buffering/limiting functionality

dar

argon2	Enable password hashing algorithm from app-crypt/argon2
dar32	Enables --enable-mode=32 option, which replace infinite by 32 bit integers
dar64	Enables --enable-mode=64 option, which replace infinite by 64 bit integers
gcrypt	Enables strong encryption support
gpg	Enables usage of asymmetric encryption algorithms
rsync	Enables linking with net-libs/librsync for delta compression support

duplicity

s3	Support for backing up to the Amazon S3 system

rear

udev	Have ReaR start backup when attaching your USB drive.

snapper

lvm	Enable LVM thinprovisioned snapshots support sys-fs/lvm2
xattr	Add support for getting and setting POSIX extended attributes, through sys-apps/attr.

tsm

tsm-cit	IBM Tivoli Common Inventory Technology
tsm-hw	Difference snapshot support for NetApp and N-Series file servers
vmware	Install vmware data protection support

app-benchmarks

filebench

auto-completion	Enable command-line autocompletion using dev-libs/libtecla

httperf

idleconn	Build with the idleconn program

ioping

netdata	Add support for netdata

ramspeed

pic	Force shared libraries to be built as PIC (this is slower)

stress-ng

keyutils	Stress test the kernel's key generation facilities via sys-apps/keyutils

sysbench

aio	Add support for AIO.
attachsql	Add support for AttachSQL.
drizzle	Add support for Drizzles.
largefile	Add support for large files.

app-cdr

brasero

libburn	Enable dev-libs/libburn backend
nautilus	Build the gnome-base/nautilus extension
playlist	Enable support for playlists through dev-libs/totem-pl-parser
tracker	Enable audio playlist search using the app-misc/tracker indexer

cdemu

cdemu-daemon	Pull app-cdr/cdemu-daemon dependency, useful in chroot environment (bug #315491). Do not disable until you know what you are doing.

dvdisaster

debug	Enable memory debugging.

gaffitter

scripts	Install additional gaffitter scripts for external programs

mirage2iso

pinentry	Support app-crypt/pinentry password input backend.

app-containers

apptainer

network	Install network plug-ins
suid	Install SUID helper binary

buildah

btrfs	Enables dependencies for the "btrfs" graph driver, including necessary kernel flags.

containerd

btrfs	Support for BTRFS snapshot driver
cri	Support for Kubernetes CRI
device-mapper	Support for device mapper snapshot driver

cri-o

btrfs	Enables dependencies for the "btrfs" graph driver, including necessary kernel flags.
device-mapper	Enables dependencies for the "devicemapper" graph driver, including necessary kernel flags.

crun

bpf	Enable in Kernel, eBPF (enhanced Berkley Packet Filter) support for managing device controllers.
criu	Enable CRIU based checkpoint/restore support

docker

btrfs	Enables dependencies for the "btrfs" graph driver, including necessary kernel flags.
container-init	Makes the a staticly-linked init system tini available inside a container.
overlay	Enables dependencies for the "overlay" graph driver, including necessary kernel flags.
overlay2	Enables dependencies for the "overlay2" graph driver, including necessary kernel flags.

docker-credential-helpers

pass	Build pass helper for the pass utility.

incus

fuidshift	Install the fuidshift binary - currently conflicts with app-containers/lxd

lxc

io-uring	Enable io_uring support, and use io_uring instead of epoll
tools	Build and install additional command line tools

nerdctl

rootless	Enables dependencies for running in rootless mode.

podman

btrfs	Enables btrfs support (graph driver) in Podman
cgroup-hybrid	Use legacy (hybrid) cgroups instead of modern (unified) cgroups
fuse	Enables fuse dependencies (fuse-overlayfs is especially useful for rootless mode).
init	Enables catatonit dependency required for podman run --init.
rootless	Enables dependencies for running in rootless mode.
wrapper	Install wrapper which lets use podman for command `docker`

runc

kmem	Enable Kernel Memory Accounting.

skopeo

btrfs	Enables dependencies for the "btrfs" graph driver.
device-mapper	Compiles with libdevmapper
rootless	Compiles with libsubid

snapd

forced-devmode	Automatically disable application confinement if feature detection fails.

app-crypt

aespipe

cpu_flags_x86_padlock	Use VIA padlock instructions, detected at run time, code still works on non-padlock processors

badkeys

dkim	Enable dkim scan mode via dev-python/dnspython.
ssh	Enable ssh scan mode via dev-python/paramiko.

ccid

twinserial	Enable twinserial reader

codecrypt

cryptopp	Build algorithms that need Crypto++ support dev-libs/crypto++

dehydrated

cron	Install cron job to sign/renew non-existent/changed/expiring certificates

eid-mw

dialogs	Enable "askaccess" dialog box, by using x11-libs/gtk+
gtk	All dialogs are available, by using x11-libs/gtk+
p11-kit	Support for app-crypt/p11-kit.

ekeyd

minimal	Only install the ekey-egd-linux service rather than the full ekeyd package.
munin	Install a plugin for net-analyzer/munin to graph statistical data from ekeyd.
usb	Build the libusb-based userland daemon for accessing the EntropyKey (alternative to the CDC USB driver). It is suggested to use this option by default, as the CDC driver in the kernel often seems to be fragile (or the gadget implementation on the EntropyKey is too buggy), and can cause various problems.

gnupg

smartcard	Build scdaemon software. Enables usage of OpenPGP cards. For other type of smartcards, try app-crypt/gnupg-pkcs11-scd. Bring in dev-libs/libusb as a dependency; enable scdaemon.
tofu	Enable support for Trust on First use trust model; requires dev-db/sqlite.
tools	Install extra tools (including gpgsplit and gpg-zip).
tpm	Enable TPM support via app-crypt/tpm2-tss and build tpm2d.
usb	Build direct CCID access for scdaemon; requires dev-libs/libusb.
user-socket	try a socket directory which is not removed by init manager at session end
wks-server	Install the wks-server

gnupg-pkcs11-scd

proxy	Build the gnupg-pkcs11-scd-prox

gpgme

common-lisp	Install common-lisp files

hashcat

brain	Enable the hashcat brain

heimdal

hdb-ldap	Adds support for LDAP as a database backend
lmdb	Add support for using dev-db/lmdb for lookup tables
otp	Adds support for one-time passwords

ima-evm-utils

tpm	Enable TPM support

johntheripper-jumbo

opencl	Build with opencl/GPU cracking support
pcap	Build with pcap support

keybase

fuse	Enable app-crypt/kbfs support

kstart

afs	Enables afs support which means you can acquire an afs token and set PAGs. It's recommended to set this USE if you need authenticated access to an AFS cell for your daemon/app.

libb2

native-cflags	Use CFLAGS as determined by configure script. These flags will enable all CPU specific features it find available, to further optimise the implementation. This discards any existing CFLAGS set in make.conf or similar.

libsecret

crypt	Enable transport encryption
gcrypt	Enable Backend library to implement transport encryption via dev-libs/libgcrypt
gnutls	Enable Backend library to implement transport encryption via net-libs/gnutls
pam	Build PAM module
tpm	Enable Trusted Platform Module support via app-crypt/tpm2-tss

libu2f-host

systemd	Use user ACLs rather than plugdev group to give user access to the HIDRAW device.

mit-krb5

doc	Creates and installs the API and implementation documentation. This is only useful if you want to develop software which depends on kerberos
keyutils	Enable for the keyring ccache using keyutils
lmdb	Add support for using dev-db/lmdb for lookup tables
openldap	Enable support for ldap as a database backend
pkinit	Enable pkinit support for the initial ticket

mkp224o

pcre	Search with a regex instead of prefix/suffix matching

onak

dynamic	Support for dynamic loading of backends
hkp	Proxying backend support

ophcrack

tables	Require the additional tables used to carry out cracking (app-crypt/ophcrack-tables)

ophcrack-tables

vistafree	Installs the free Vista ophcrack tables
xpfast	Installs the fast XP ophcrack tables
xpsmall	Installs the small free XP ophcrack tables

pinentry

efl	Build dev-libs/efl based pinentry

qca

botan	Enable botan plugin
gcrypt	Enable gcrypt plugin
gpg	Enable GnuPG plugin
logger	Enable logger plugin
nss	Enable NSS plugin
pkcs11	Enable PKCS#11 plugin
sasl	Enable SASL plugin
softstore	Enable softstore plugin

rpm-sequoia

nettle	Use dev-libs/nettle as a crypto backend
openssl	Use dev-libs/openssl as a crypto backend

seahorse

ldap	Enable seahorse to manipulate GPG keys on a LDAP server.

swtpm

fuse	Support sys-fs/fuse based /dev/tpm interface

tpm-tools

pkcs11	Build Token data management utilities based on OpenCryptoki's (dev-libs/opencryptoki) PKCS#11 implementation.

tpm2-pkcs11

fapi	Enable feature API backend

tpm2-tools

fapi	Enable feature API tools

tpm2-totp

plymouth	Add sys-boot/plymouth support

tpm2-tss

fapi	Enable feature API (requires openssl as crypto backend)
mbedtls	Use net-libs/mbedtls as crypto engine
openssl	Use dev-libs/openssl as crypto engine
policy	Enable policy library (requires openssl as crypto backend)

zulucrypt

kwallet	Enable encrypted storage of passwords with kde-frameworks/kwallet
udev	Whether udev will be consulted when deciding if a volume is system or not

app-dicts

aspell-be

classic	Support classic spelling by default

gwaei

hunspell	Enable app-text/hunspell spellchecking and morphological analysis
mecab	Enable app-text/mecab support

myspell-pt

preao	Use the pre ortographic agreement version of the dictionary

app-doc

csound-manual

html	Install HTML documentation

devmanual

offline	Use alternative minimal stylesheet instead of Tyrian theme

kicad-doc

html	Generate documentation in HTML format
pdf	Generate documentation in PDF format

linuxfromscratch

htmlsingle	Install all-on-one-page HTML version.

pms

html	Generate and install PMS as .html as well
twoside	Enable two-sided layout suitable for printing

pms-bin

html	Install PMS as .html as well

tldp-howto

html	Install multi-chapter HTML docs
htmlsingle	Install all-on-one-page HTML docs
pdf	Install pdf docs
text	Install plain-text docs

app-editors

bluefish

gucharmap	Enable gucharmap dictionary plugin
spell	Enable spell checking capabilities via enchant library

emacs

athena	Enable the MIT Athena widget set (x11-libs/libXaw)
dynamic-loading	Enable loading of dynamic libraries (modules) at runtime
games	Support shared score files for games
gfile	Use gfile (dev-libs/glib) for file notification
gmp	Use the GNU multiple precision arithmetic library (dev-libs/gmp) instead of the bundled mini-gmp subset
gsettings	Use gsettings (dev-libs/glib) to read the system font name
gzip-el	Compress bundled Emacs Lisp source
harfbuzz	Use media-libs/harfbuzz as text shaping engine
imagemagick	Use media-gfx/imagemagick for image processing
jit	Compile with Emacs Lisp native compiler support via libgccjit
json	Compile with native JSON support using dev-libs/jansson
libxml2	Use dev-libs/libxml2 to parse XML instead of the internal Lisp implementations
mailutils	Retrieve e-mail using net-mail/mailutils instead of the internal movemail substitute
source	Install C source files and make them available for find-function
threads	Add elisp threading support
toolkit-scroll-bars	Use the selected toolkit's scrollbars in preference to Emacs' own scrollbars
tree-sitter	Support the dev-libs/tree-sitter parsing library
wide-int	Prefer wide Emacs integers (typically 62-bit). This option has an effect only on 32-bit systems, where it increases the maximum buffer size from 0.5 to 2 GiB, at the cost of 10% to 30% Lisp slowdown.

fe

sendmail	Send mail after editor abend

featherpad

X	Link application against X11 libraries which adds support for virtual desktop awareness and tab DND

gedit-plugins

charmap	Insert special characters just by clicking on them
git	Shows document changes related to git's HEAD
terminal	Embed a terminal in the bottom pane

gnome-latex

latexmk	Install dev-tex/latexmk (used by default for the build tools)
rubber	Install dev-tex/rubber (can be used for the build tools)

gvim

crypt	Use dev-libs/libsodium for crypto support
cscope	Enable cscope interface
netbeans	Include netbeans external editor integration support
racket	Enable support for Scheme using dev-scheme/racket

helix

grammar	Build and install grammar language files

jasspa-microemacs

nanoemacs	Build NanoEmacs instead of MicroEmacs

joe

xterm	Enable full xterm clipboard support

leafpad

emacs	Enable Emacs key theme

mousepad

shortcuts	Build the "shortcuts" plugin

nano

debug	Enable debug messages and assert warnings. Note that these will all be sent straight to stderr rather than some logging facility.
justify	Enable justify/unjustify functions for text formatting.
magic	Add magic file support (sys-apps/file) to automatically detect appropriate syntax highlighting
minimal	Disable all fancy features, including ones that otherwise have a dedicated USE flag (such as spelling).

neovim

nvimpager	Install nvimpager symlink to less.sh macro

okteta

designer	Build plugins for dev-qt/designer

qhexedit2

gui	Install Qt5 hex editor

tea

aspell	Enable spellchecking using app-text/aspell

vim

X	Link console vim against X11 libraries to enable title and clipboard features in xterm
crypt	Use dev-libs/libsodium for crypto support
cscope	Enable cscope interface
racket	Enable support for Scheme using dev-scheme/racket
terminal	Enable terminal emulation support
vim-pager	Install vimpager and vimmanpager links

vis

tre	more memory efficient regex search using dev-libs/tre

vscode

egl	Use EGL platform, enables smooth rending in high refresh rate monitors on X11/Xwayland
wayland	Run in wayland mode under wayland sessions, xwayland otherwise. This flag doesn't affect x11 sessions.

vscodium

egl	Use EGL platform, enables smooth rending in high refresh rate monitors on X11/Xwayland
wayland	Run in wayland mode under wayland sessions, xwayland otherwise. This flag doesn't affect x11 sessions.

xemacs

athena	Chooses the MIT Athena widget set
bignum	Support for OpenSSL bignum implementation
dnd	Enables support for the x11-libs/dnd drag-n-drop library
pop	Support POP for mail retrieval
xim	Enable X11 XiM input method

zed

gles	Use simplified OpenGLES instead of full-scale OpenGL

app-emacs

auctex

preview-latex	Use bundled preview-latex

bbdb

tex	Install plain TeX support files
vm	Add support for app-emacs/vm
wanderlust	Add support for app-emacs/wanderlust

calfw

howm	Add support for the app-emacs/howm note-taking tool

elscreen

wanderlust	Include support for app-emacs/wanderlust

emacs-common

games	Support shared score files for games
gsettings	Install schema file for gsettings (dev-libs/glib)

emacs-w3m

gzip-el	Compress bundled Emacs Lisp source

flim

oauth2	Support OAuth2 authentication (app-emacs/oauth2)

gap-mode

completion	Install GAP backend for app-emacs/company-mode to "complete anything."
lint	Support automatically linting GAP code via app-emacs/flycheck and dev-gap/gaplint.

mu-cite

bbdb	Include support for app-emacs/bbdb

org-mode

odt-schema	Install non-free schema files for OpenDocument Text exporter

remember

bbdb	Include support for app-emacs/bbdb
planner	Include support for app-emacs/planner

slime

xref	Install xref.lisp cross-referencing tool

sly

xref	Install xref.lisp cross-referencing tool

vm

bbdb	Include support for app-emacs/bbdb

wanderlust

bbdb	Include support for app-emacs/bbdb

wikipedia-mode

outline-magic	Enable support for outline-mode extensions (app-emacs/outline-magic)

app-emulation

86Box

experimental	Enable hardware from devbranch, which may be unstable or unusable.
fluidsynth	Enable MIDI support through media-sound/fluidsynth.
munt	Enable MIDI MT-32 support through media-libs/munt-mt32emu.
new-dynarec	Enable new dynamic recompiler from PCem 15, which should provide an even better emulation speed.

aranym

clipboard	Enable bidirectional clipboard transfer between the host and FreeMiNT
jit	Build Just-In-Time compiler variant with increased performance
lilo	Enable support for directly booting kernels such as Linux
osmesa	Allow images to be rendered in memory using the host CPU
pmmu	Build full PMMU variant, required for running mainline Linux
standard	Build standard (no JIT or PMMU) variant

bochs

3dnow	Enable support for emulating 3DNow! instructions (incomplete)
avx	Enable support for emulating Advanced Vector Extensions (AVX)
debugger	Enable debugger (slows down emulation)
gdb	Enable support for the remote GDB stub
x86-64	Enable support for emulation of 64-bit CPUs

crossover-bin

capi	Enable ISDN support via CAPI
osmesa	Add support for OpenGL in bitmaps using libOSMesa
pcap	Support packet capture software (e.g. wireshark)

dosemu

fluidsynth	use media-sound/fluidsynth for MIDI emulation

dxvk

crossdev-mingw	Use sys-devel/crossdev for the toolchain rather than dev-util/mingw64-toolchain (requires manual setting up)
d3d10	Enable support for DirectX 10 (d3d10.dll)
d3d11	Enable support for DirectX 11 (d3d11.dll)
d3d8	Enable support for DirectX 8 (d3d8.dll)
d3d9	Enable support for DirectX 9 (d3d9.dll)
dxgi	Enable support for the DirectX Graphics Infrastructure (dxgi.dll)

faudio

dumpvoices	FAudio dumps buffer data to individual files with RIFF/XWMA headers, usable with players like ffplay/testxwma.

fs-uae

fmv	Enable support for CD32 FMV (full motion video)
glew	Enable support for The OpenGL Extension Wrangler Library (media-libs/glew)

fs-uae-launcher

lha	Enable LHA archive support

fuse

backend-X	Use X11 rendering backend
backend-fbcon	Use framebuffer rendering backend
backend-gtk3	Use Gtk+ rendering backend
backend-sdl	Use SDL rendering backend
backend-svga	Use svgalib rendering backend
memlimit	Add compile-time memory usage limiting

fuse-utils

gcrypt	Use dev-libs/libgcrypt for low-level crypto of some features, including logfiles.

grub-xen-host

pvh	Build an additional grub bin for pvh.

hercules-sdl

object-rexx	Enable REXX support via Open Object Rexx (dev-lang/oorexx)
regina-rexx	Enable REXX support via Regina Rexx (dev-lang/regina-rexx)

libcacard

passthrough	Enable smartcard passthrough support via sys-apps/pcsc-lite

libguestfs

erlang	Build Erlang bindings
fuse	Enable image mount support via sys-fs/fuse
inspect-icons	Use media-gfx/icoutils for accessing/inspecting icon file within images
libvirt	Use app-emulation/libvirt to manipulate VMs
systemtap	Use dev-debug/systemtap to inspect VM via "probes"

libspectrum

gcrypt	Use dev-libs/libgcrypt for low-level crypto of some features, including logfiles.

libvirt

dtrace	Enable dtrace support via dev-debug/systemtap
firewalld	DBus interface to iptables/ebtables allowing for better runtime management of your firewall.
fuse	Allow LXC to use sys-fs/fuse for mountpoints
glusterfs	Enable GlusterFS support via sys-cluster/glusterfs
iscsi	Allow using an iSCSI remote storage server as pool for disk image storage
iscsi-direct	Allow using libiscsi for iSCSI storage pool backend
libssh	Use net-libs/libssh to communicate with remote libvirtd hosts, for example: qemu+libssh://server/system
libssh2	Use net-libs/libssh2 to communicate with remote libvirtd hosts, for example: qemu+libssh2://server/system
libvirtd	Builds the libvirtd daemon as well as the client utilities instead of just the client utilities
lvm	Allow using the Logical Volume Manager (sys-fs/lvm2) as pool for disk image storage
lxc	Support management of Linux Containers virtualisation (app-containers/lxc)
nbd	Allow using sys-block/nbdkit to access network disks
nfs	Allow using Network File System mounts as pool for disk image storage
numa	Use NUMA for memory segmenting via sys-process/numactl and sys-process/numad
openvz	Support management of OpenVZ virtualisation (openvz-sources)
parted	Allow using real disk partitions as pool for disk image storage, using sys-block/parted to create, resize and delete them.
pcap	Support auto learning IP addreses for routing
qemu	Support management of QEMU virtualisation (app-emulation/qemu)
rbd	Enable rados block device support via sys-cluster/ceph
virt-network	Enable virtual networking (NAT) support for guests. Includes all the dependencies for NATed network mode. Effectively any network setup that relies on libvirt to setup and configure network interfaces on your host. This can include bridged and routed networks ONLY if you are allowing libvirt to create and manage the underlying devices for you. In some cases this requires enabling the 'netcf' USE flag (currently unavailable).
virtiofsd	Drag in virtiofsd dependency app-emulation/virtiofsd
virtualbox	Support management of VirtualBox virtualisation (app-emulation/virtualbox)
wireshark-plugins	Build the net-analyzer/wireshark plugin for the Libvirt RPC protocol
xen	Support management of Xen virtualisation (app-emulation/xen)
zfs	Enable ZFS backend storage sys-fs/zfs

nemu

network-map	Adds possibility of exporting network map to SVG
ovf	Adds support for OVA/OVF import
remote-api	Adds API for remote control
spice	Adds Spice protocol support
vnc-client	Adds support for external VNC client

open-vm-tools

deploypkg	Build deploypkg plugin
dnet	Enable support for nicinfo
doc	Generate API documentation
fuse	Enable vmblock-fuse/vmhgfs-fuse
gtkmm	Compile with Gtkmm and sigc++ (Recommended)
multimon	Enable multimon (Requires X)
resolutionkms	Build the linux/unix resolutionkms module
vgauth	Build vgauth

pcem

networking	Enable support for emulation of network cards.

punes

cg	Add support for Nvidia CG Toolkit

q4wine

ico	Enable ico support via media-gfx/icoutils
iso	Support unprivileged mounting of ISO9660 images via sys-fs/fuseiso
wineappdb	Enable Wine AppDB browser support

qemu

accessibility	Adds support for braille displays using brltty
aio	Enables support for Linux's Async IO
alsa	Enable alsa output for sound emulation
bpf	Enable eBPF support for RSS implementation.
capstone	Enable disassembly support with dev-libs/capstone
curl	Support ISOs / -cdrom directives via HTTP or HTTPS.
fdt	Enables firmware device tree support
fuse	Enables FUSE block device export
glusterfs	Enables GlusterFS cluster fileystem via sys-cluster/glusterfs
gnutls	Enable TLS support for the VNC console server. For 1.4 and newer this also enables WebSocket support. For 2.0 through 2.3 also enables disk quorum support.
io-uring	Enable efficient I/O via sys-libs/liburing.
iscsi	Enable direct iSCSI support via net-libs/libiscsi instead of indirectly via the Linux block layer that sys-block/open-iscsi does.
jemalloc	Enable jemalloc allocator support
jpeg	Enable jpeg image support for the VNC console server
keyutils	Support Linux keyrings via sys-apps/keyutils
multipath	Enable multipath persistent reservation passthrough via sys-fs/multipath-tools.
ncurses	Enable the ncurses-based console
nfs	Enable NFS support
numa	Enable NUMA support
pin-upstream-blobs	Pin the versions of BIOS firmware to the version included in the upstream release. This is needed to sanely support migration/suspend/resume/snapshotting/etc... of instances. When the blobs are different, random corruption/bugs/crashes/etc... may be observed.
pipewire	Enable pipewire output for sound emulation
plugins	Enable qemu plugin API via shared library loading.
png	Enable png image support for the VNC console server
pulseaudio	Enable pulseaudio output for sound emulation
rbd	Enable rados block device backend support, see https://docs.ceph.com/en/mimic/rbd/qemu-rbd/
sdl	Enable the SDL-based console
sdl-image	SDL Image support for icons
slirp	Enable TCP/IP in hypervisor via net-libs/libslirp
spice	Enable Spice protocol support via app-emulation/spice
ssh	Enable SSH based block device support via net-libs/libssh2
static	Build the User and Software MMU (system) targets as well as tools as static binaries
static-user	Build the User targets as static binaries
systemtap	Enable SystemTap/DTrace tracing
usb	Enable USB passthrough via dev-libs/libusb
usbredir	Use sys-apps/usbredir to redirect USB devices to another machine over TCP
vde	Enable VDE-based networking
vhost-net	Enable accelerated networking using vhost-net, see https://www.linux-kvm.org/page/VhostNet
virgl	Enable experimental Virgil 3d (virtual software GPU)
virtfs	Enable VirtFS via virtio-9p-pci / fsdev. See https://wiki.qemu.org/Documentation/9psetup
vte	Enable terminal support (x11-libs/vte) in the GTK+ interface
xattr	Add support for getting and setting POSIX extended attributes, through sys-apps/attr. Requisite for the virtfs backend.
xdp	Enable support for XDP through net-libs/xdp-tools
xen	Enables support for Xen backends

ski

debug	enable extra binary emulation debugging via sys-libs/binutils-libs

spice

smartcard	Enable smartcard remoting using app-emulation/libcacard

uade

fuse	Enable sys-fs/fuse uadefs frontend for on-the-fly WAV conversion

vice

ethernet	Enable ethernet emulation
headless	Include the headless variant of the emulator
mpg123	Enable mp3@64 cartridge support
parport	Enable parallel port SID support
pci	Enable PCI device discovery using sys-apps/pciutils

virt-manager

policykit	Enables sys-auth/polkit authentication support, required when using app-emulation/libvirt with PolicyKit authentication
sasl	Depend on the proper libraries needed to connect to SASL-enabled libvirtd instances (e.g. Kerberos-protected instances).

virt-viewer

libvirt	Support connecting to virtual machines managed by libvirt.
spice	Support connecting to SPICE-enabled virtual machines.
vnc	Support connecting to VNC-enabled virtual machines.
vte	Enable terminal support (x11-libs/vte) in the GTK+ interface

virt-what

dmi	Use sys-apps/dmidecode to read firmware data

virtualbox

dtrace	Install dtrace Extension Pack.
headless	Build without any graphic frontend.
lvm	Build VBoxVolInfo that needs devicemapper from sys-fs/lvm2.
pax-kernel	Apply patch needed for pax enabled kernels.
sdk	Enable building of SDK.
udev	Controls installation of special USB udev rules.
vboxwebsrv	Build and install the VirtualBox webservice.
vde	Support for VDE networking via net-misc/vde.
vmmraw	Enable 32-bit support on a 64-bit kernel.

virtualbox-kvm

dtrace	Install dtrace Extension Pack
hardened	Enable hardening and install binaries SUID
lvm	Build VBoxVolInfo that needs devicemapper from sys-fs/lvm2.
sdk	Enable building of SDK
udev	Controls installation of special USB udev rules.
vboxwebsrv	Build and install the VirtualBox webservice
vde	Support for VDE networking via net-misc/vde
vmmraw	Enable 32-bit support on a 64-bit kernel.

vkd3d

spirv-tools	Enable SPIRV shader debugging support using dev-util/spirv-tools

vkd3d-proton

crossdev-mingw	Use sys-devel/crossdev for the toolchain rather than dev-util/mingw64-toolchain (requires manual setting up)
extras	Install extra tools and demos in /usr/lib/vkd3d-proton

wine-gecko

shared	Install pre-unpacked files which do not need to be copied into the Wine prefix

wine-mono

shared	Install pre-unpacked files which do not need to be copied into the Wine prefix (note that this requires the default top-level Z: drive to be kept for out-of-prefix files to be readable)

wine-proton

crossdev-mingw	Use sys-devel/crossdev for the toolchain rather than dev-util/mingw64-toolchain (requires manual setting up)
gecko	Enable mshtml support using app-emulation/wine-gecko
mono	Enable .NET support using app-emulation/wine-mono
osmesa	Enable off-screen rendering (OpenGL in bitmaps) support
perl	Install helpers that require perl (winedump/winemaker)
sdl	Enable gamepad support using media-libs/libsdl2
vkd3d	Enable DirectX 12 support using app-emulation/vkd3d
wow64	Enable running 32bit applications without 32bit ELF multilib by mapping to 64bit calls (experimental, *may* have worse/unusable OpenGL performance or other issues compared to USE=abi_x86_32, also lacks 16bit support) -- still need dev-util/mingw64-toolchain with abi_x86_32 which itself does not need multilib

wine-staging

capi	Enable ISDN support using net-libs/libcapi
crossdev-mingw	Use sys-devel/crossdev for the toolchain rather than dev-util/mingw64-toolchain (requires manual setting up)
dos	Pull in games-emulation/dosbox to run DOS applications
gecko	Enable mshtml support using app-emulation/wine-gecko
mingw	Build PE files using a MinGW toolchain for better compatibility
mono	Enable .NET support using app-emulation/wine-mono
netapi	Enable support for configuring remote shares using net-fs/samba
osmesa	Enable off-screen rendering (OpenGL in bitmaps) support
pcap	Support packet capture software (e.g. wireshark)
perl	Install helpers that require perl (winedump/winemaker)
samba	Pull in net-fs/samba with winbind for NTLM auth support
sdl	Enable gamepad support using media-libs/libsdl2
wow64	Enable running 32bit applications without 32bit ELF multilib by mapping to 64bit calls (experimental, *may* have worse/unusable OpenGL performance or other issues compared to USE=abi_x86_32, also lacks 16bit support) -- still need dev-util/mingw64-toolchain with abi_x86_32 which itself does not need multilib

wine-vanilla

capi	Enable ISDN support using net-libs/libcapi
crossdev-mingw	Use sys-devel/crossdev for the toolchain rather than dev-util/mingw64-toolchain (requires manual setting up)
dos	Pull in games-emulation/dosbox to run DOS applications
gecko	Enable mshtml support using app-emulation/wine-gecko
mingw	Build PE files using a MinGW toolchain for better compatibility
mono	Enable .NET support using app-emulation/wine-mono
netapi	Enable support for configuring remote shares using net-fs/samba
osmesa	Enable off-screen rendering (OpenGL in bitmaps) support
pcap	Support packet capture software (e.g. wireshark)
perl	Install helpers that require perl (winedump/winemaker)
samba	Pull in net-fs/samba with winbind for NTLM auth support
sdl	Enable gamepad support using media-libs/libsdl2
vkd3d	Enable DirectX 12 support using app-emulation/vkd3d
wow64	Enable running 32bit applications without 32bit ELF multilib by mapping to 64bit calls (experimental, *may* have worse/unusable OpenGL performance or other issues compared to USE=abi_x86_32, also lacks 16bit support) -- still need dev-util/mingw64-toolchain with abi_x86_32 which itself does not need multilib

winetricks

rar	Pull in app-arch/unrar for extraction of rar-compressed game files

x48

readline	Enables support for libreadline

xe-guest-utilities

xenstore	Use xenstore binaries bundled by Citrix instead of building app-emulation/xen-tools

xen

boot-symlinks	Symlink xen.gz variants in /boot, disable on fat filesystems
flask	Enable the Flask XSM module from NSA
uefi	Adds UEFI boot support, requires LDFLAG -melf_x86_64 for amd64

xen-tools

api	Build the C libxenapi bindings
hvm	Enable support for hardware based virtualization (VT-x,AMD-v)
ipxe	Enable ipxe support
ovmf	Enable support to boot UEFI guest vm, needed by hvm
pygrub	Install the pygrub boot loader
qemu	Enable IOEMU support via the use of qemu-dm
qemu-traditional	Build the old qemu traditional device model (useful only if you cannot change to the new device model e.g. Windows VMs)
rombios	Enable rombios support, needed by ipxe
screen	Enable support for running domain U console in an app-misc/screen session
system-ipxe	Using sys-firmware/ipxe instead of the bundled one
system-qemu	Using app-emulation/qemu instead of the bundled one
system-seabios	Using sys-firmware/seabios instead of the bundled one

xtrs

ls-dos	Install LS-DOS disk images for Model 4P

app-eselect

eselect-php

fpm	Enable the FastCGI Process Manager SAPI

eselect-wine

xdg	Set XDG_DATA_DIRS to use the selected wine.desktop, allows e.g. 'xdg-open my.exe' for file managers

app-forensics

afflib

fuse	Enable extra fuse thingies
qemu	Enable qemu stuff
s3	Enable support for Amazon S3

aide

curl	Use curl for http,https and ftp backends
e2fs	Enable support for checking file attributes on ext2/ext3/ext4 filesystems

chkrootkit

cron	Install cron script for weekly rootkit scans

honggfuzz

clang	Enable clang support (pull sys-libs/blocksruntime dependency).

lynis

cron	Install /etc/cron.* files

sleuthkit

aff	Enable extra aff formats
ewf	Enable libewf support

volatility3

crypt	support plugins that decrypt passwords, password hashes, etc.
disasm	support plugins that perform malware analysis and disassemble code
jsonschema	improve error messages regarding improperly configured ISF files
leechcore	support memory acquisition via leechcore
snappy	support AVMLs native compression format
yara	support YARA pattern matching engine

yara

cuckoo	Enable cockoo module
dex	Enable dex module
dotnet	Enable dotnet module
macho	Enable macho module
magic	Enable magic module
profiling	Enable rules profiling
python	Pulls in python binding via dev-python/yara-python

app-i18n

fcitx

autostart	Enable XDG-compatible autostart of Fcitx
emoji	Enable emoji loading for CLDR
enchant	Enable Enchant backend (using app-text/enchant) for spelling hinting
gtk2	Install input method module for GTK+ 2
gtk3	Install input method module for GTK+ 3
keyboard	Enable key event translation with XKB and build keyboard engine
opencc	Enable OpenCC engine (using app-i18n/opencc) for converter between Simplified Chinese and Traditional Chinese
pango	Enable support for x11-libs/pango
presage	Enable presage for word predication (not stable)
server	Build a fcitx as server, disable this option if you want to use fcitx as an embedded library
table	Install table input methods for Simplified Chinese
xkb	Enable support for XKB (required for fcitx-xkb, fcitx-xkbdbus, part of fcitx-keyboard)

fcitx-chinese-addons

cloudpinyin	Build cloud pinyin addon
data	Build data
gui	Enable GUI support (qt5 or qt6)
opencc	Enable support for conversion between Traditional and Simplified Chinese
qt5	Enable configure qt5
webengine	Enable built-in browser using dev-qt/qtwebengine

fcitx-configtool

config-qt	Enable fcitx5-config-qt
kcm	Enable KDE KCM support
test	Enable Test

fcitx-gtk

gtk2	Install input method module for GTK+ 2
gtk3	Enable support for GTK+3
gtk4	Enable support for GTK 4
onlyplugin	Build only plugin
snooper	Enable key snooper for gtk app

fcitx-libpinyin

dictionary-manager	Install dictionary manager

fcitx-lua

dlopen	Use dlopen to load lua library

fcitx-qt

onlyplugin	Build only plugin
qt6	Build support for QT6
staticplugin	Build plugin as static

fcitx-rime

configuration-tool	Install configuration tool

fcitx-unikey

macro-editor	Install macro editor

ibus

emoji	Enable support for Emoji
gtk2	Enable the GTK-2 input method module
gtk3	Enable the GTK-3 input method module
gtk4	Enable the GTK-4 input method module
unicode	Enable support for Unicode choice

ibus-handwrite

zinnia	Enable support for app-i18n/zinnia

ibus-libpinyin

boost	Compile against dev-libs/boost libraries
opencc	Enable support for app-i18n/opencc

ibus-pinyin

boost	Enable support for dev-libs/boost

im-chooser

xfce	Enable support for XFCE panel

imsettings

xfconf	Enable support for xfce-base/xfconf

libime

data	Build data

librime

debug	Enable debugging (including logging of input of RIME input methods)

mozc

fcitx4	Enable support for app-i18n/fcitx 4
fcitx5	Enable support for app-i18n/fcitx 5
gui	Install graphical user interface tool (mozc_tool)
ibus	Enable support for app-i18n/ibus
renderer	Enable native candidate window

pyzy

boost	Enable support for dev-libs/boost
doc	Generate API documentation
opencc	Enable support for app-i18n/opencc

rime-data

extra	Install extra packages

scim

gtk3	Enable support for x11-libs/gtk+:3

scim-anthy

gtk3	Enable support for x11-libs/gtk+:3
kasumi	Use Anthy dictionary maintenance tool (app-dicts/kasumi)

tomoe

hyperestraier	Enable support for app-text/hyperestraier

uim

anthy	Enable support for app-i18n/anthy
eb	Enable support for dev-libs/eb
gtk2	Enable support for x11-libs/gtk+:2
skk	Enable support for app-i18n/skk-jisyo

app-laptop

hdapsd

libconfig	Require dev-libs/libconfig to allow the daemon to read a configuration file at startup

ibam

gkrellm	Enable building of app-admin/gkrellm module

laptop-mode-tools

apm	Add APM (Advanced Power Management) support

pbbuttonsd

ibam	Enable support for Intelligent Battery Monitoring
macbook	Enable support for the Macbook and Macbook Pro

thinkfan

atasmart	include libatasmart support to get disc temperature
nvidia	allow thinkfan to read GPU temperature from the proprietary nVidia driver
yaml	use YAML format for config file

tp_smapi

hdaps	Install a compatible HDAPS module

app-metrics

collectd

contrib	Install user-contributed files in the doc directory
filecaps	When set collectd daemon will have set required capabilities to run most plugins even if run as unprivileged user
java	Must be set (workaround for java-pkg-opt-2 eclass limitation) when you want java or genericjmx plugin
udev	Enable optional udev usage in disk plugin; Required for smart plugin
xfs	Enable optional capability to filter on XFS file system in df plugin; Requires XFS headers from sys-fs/xfsprogs

node_exporter

systemd	Enables systemd collector by default

prometheus-podman-exporter

btrfs	Collect metrics for btrfs filesystem

app-misc

FreeSSM

small-resolution	Build the app for small resolution screeens

anki

gui	Enable support for a graphical user interface. Disable for standalone sync server.

blink1

mini-tool	Build and install command-line mini-tool blink1-mini-tool (normally used for embedded devices)
server	Build and install REST API server (currently hard-coded to TCP port 8080)
tool	Build and install command-line tool blink1-tool

broot

X	X11 clipboard interaction

byobu

screen	Use app-misc/screen as the default backend

ca-certificates

cacert	Include root/class3 certs from CAcert (https://www.cacert.org/)

carbon-c-relay

client	build and install sendmetric client utility
lz4	add support for LZ4 compressed transport
oniguruma	use dev-libs/oniguruma as regex implementation
pcre2	use dev-libs/libpcre2 as regex implementation
snappy	add support for Snappy compressed transport

ddccontrol

pci	enable direct PCI memory access (the setuid ddcpci util)

ddcutil

drm	Use x11-libs/libdrm for more verbose diagnostics.
usb-monitor	Adds support for monitors attached via USB.
user-permissions	Adds a udev rules to allow non-root users in the i2c group to access the /dev/i2c-* devices. If usb-monitor is selected, users will need to be added to the video group to access the USB monitor. Otherwise, only root will be able to use ddcutil.

digitemp

ds2490	Build support for the ds2490 sensor
ds9097	Build support for the ds9097 sensor
ds9097u	Build support for the ds9097u sensor

ebusd

contrib	Compile and install additional user contribued plugins.
knx	Enable support for connecting to KNX.
mqtt	Enable support for connecting to MQTT.

fastfetch

chafa	Enables text/graphics renderer with media-gfx/chafa
ddcutil	Use app-misc/ddcutil to query monitor settings
drm	Enables support for X.org's x11-libs/libdrm
elf	Use libelf to extract strings from binaries
osmesa	Enables offscreen rendering support from media-libs/mesa
vulkan	Enables reading GPU via media-libs/vulkan-loader
xfce	Enables support for XFCE config
xrandr	Enables support for Xrandr

g810-led

hidapi	Use dev-libs/hidapi instead of virtual/libusb for talking to the device (advertised to be faster)

geoclue

modemmanager	Enable geolocation through 3G or GPS enabled hardware through net-misc/modemmanager.
zeroconf	Enable retrieval of GPS location from Android devices with https://wiki.gnome.org/Apps/GeoclueShare

gramps

geo	Enable rendering of geographical data using sci-geosciences/osm-gps-map
rcs	Adds support for family tree archives via dev-vcs/rcs
reports	All external software that is needed for graphical reports will be installed

graphlcd-base

fontconfig	Add support for media-libs/fontconfig font names.
freetype	Add support for media-libs/freetype.
graphicsmagick	Add support for media-gfx/graphicsmagick.
imagemagick	Add support for media-gfx/imagemagick.

irtrans-irserver

mono	Enable mono support

jdupes

dedupe	Enable deduplication support

jp

jpp	Install jpp which is an extended superset of the jp CLI for JMESPath

jpipe

jp-symlink	Install a jp symlink that points to jpipe.
jpp-symlink	Install a jpp symlink that points to jpipe.

jq

oniguruma	Use dev-libs/oniguruma for regular expression support

kryoflux-dtc

demos	Install example floppy game files.
fast-firmware	Install fast firmware instead of slow firmware.

lcd4linux

apm	Enable the APM plugin.
asterisk	Enable the Asterisk plugin.
button-exec	Enable the Button plugin, to execute something on keypress.
cpuinfo	Enable the cpuinfo plugin.
dbus	Enable the dbus plugin.
diskstats	Enable the diskstats plugin.
dvb	Enable support for the DVB plugin.
event	Enable the event plugin.
exec	Enable the exec plugin, to read output from external programs.
fifo	Enable the FIFO (First-In, First-Out) plugin.
file	Enable the file plugin, to read from input from files.
gps	Enable the gps plugin, for reading gps coordinates.
hddtemp	Enable the hddtemp plugin, to read from the hddtemp daemon.
huawei	Enable the huawei plugin, to read from a huawei device.
i2c-sensors	Enable the i2c_sensors plugin, to read sensor data.
iconv	Enable the iconv plugin, to convert between encodings.
isdn	Enable the isdn plugin, to get information about ISDN.
kvv	Enable the kvv plugin, to get realtime train schedule from the Karlsruher Verkehrsverbund.
loadavg	Enable the loadavg plugin, to get stats load
meminfo	Enable the meminfo plugin, to get memory statistics.
mpd	Enable the mpd plugin, to read from the Music Player Daemon.
mpris-dbus	Enable the mpris plugin, to read data via dbus for mpris.
mysql	Enable the mysql plugin, to get mysql database information.
netdev	Enable the netdev plugin, to get interface statistics.
netinfo	Enable the netinfo plugin, to get more interface statistic.
outb	Enable raw i/o access.
pop3	Enable the pop3 plugin, to get notified about new mails.
proc-stat	Enable the proc_stat plugin, to read data from the proc file system.
python	Enable support for dev-lang/python and enable the python plugin, to execute own python scripts.
qnaplog	Enable the qnaplog plugin, to read a log from a QNAP device.
raspi	Enable the raspi plugin, to read sensor data from a Raspberry Pi.
sample	Enable the sample plugin.
statfs	Enable the statfs plugin, to get statistics about the file system.
uname	Enable the uname plugin, to get the output of uname.
uptime	Enable the uptime plugin.
w1retap	Enable the w1retap plugin.
wireless	Enable the wireless plugin, to get wireless statistics.

lcdproc

ethlcd	Enable support for ethlcd in the hd44780 driver.
extra-charmaps	Enable extra language specific charmaps.
menu	Enable menu support in the lcdproc client.
nfs	Display NFS filesystem stats in the lcdproc client.
png	Enable support for media-libs/libpng in the glcd driver.
samba	Display SMBFS filesystem stats in the lcdproc client.
test-menu	Enable test menu support for the lcdproc server.
truetype	Enable support for media-libs/freetype in the glcd driver.

libdatovka

openssl	Use openssl backend

lirc

audio	Support using an audio device connected to an IR receiver
devinput	Support the devinput input device
ftdi	Support FTDI devices
gtk	Include GTK support which enables the use of lirc-setup
inputlirc	Add a dependency on app-misc/inputlircd
uinput	Enable support for uinput

mc

edit	Compile and install the mcedit application
sftp	Add support for sftp (uses net-libs/libssh2 for it).
slang	Use sys-libs/slang instead of sys-libs/ncurses.

mime-types

nginx	Enable mime-types support for www-servers/nginx package

mosquitto

bridge	Enable bridge support in the MQTT broker.
persistence	Store messages and subscriptions to a file.
srv	Include SRV lookup support.
websockets	Support the WebSocket protocol.

muttprint

doc	Builds documentation

neofetch

X	Enable support for detecting DEs, WMs, screen resolutions, and showing images from an X terminal

nnn

8contexts	Enable 8 contexts (instead of 4)
colemak	Key bindings for Colemak keyboard layout
emoji	Display icons using emoji
gitstatus	Add git status column to the detail view
icons	Display icons using icons-in-terminal
namefirst	Print filenames first in the detail view
nerdfonts	Display icons using nerdfonts icons
qsort	Use Alexey Tourbin's quick sort implementation
restorepreview	Add pipe to close and restore preview-tui for internal undetached edits

note

general	Add support for ascii flatfile backend
text	Add support for text backend

ola

ftdi	Support FTDI devices
http	Enable built-in Web UI
rdm-tests	Install RDM responder tests

pax-utils

python	Install a more powerful/faster version of lddtree

recoll

camelcase	Enable indexing for camelCase sentences and words
chm	Enable CHM file support via dev-python/pychm
inotify	Use the Linux Kernel notification subsystem for monitoring file alterations in realtime
session	Stop monitoring file alterations when X11 session terminates
webengine	Use dev-qt/qtwebengine for fancy result list display

rlwrap

debug	Enable debug

screen

multiuser	Enable multiuser support (by setting correct permissions)
nethack	Express error messages in nethack style

screenfetch

X	Use the media-gfx/scrot package to take screenshots

sphinx

id64	use 64-bit document and word IDs
mariadb	Add mariadb database support
stemmer	Enable language stemming support

task

sync	Enable "task sync" support

tmux

utempter	Include libutempter support

tracker

miners	Install the app-misc/tracker-miners package for actual data mining support for tracker
stemmer	Add word stemming via dev-libs/snowball-stemmer.

tracker-miners

cue	Enable cue sheet parsing
gsf	Enable gnome-extra/libgsf based data extractor and for ODT.
iptc	Enable extraction of IPTC data from pictures
iso	Enable extraction of metadata from ISO disk images
playlist	Add support for playlists
xps	Add support for XPS file format through app-text/libgxps.

unfoo

minimal	Do not install all support archive binaries

vcontrold

vclient	Build the vclient helper program to talk to vcontrold
vsim	Build the vsim helper program (simulates the heating's answers, for development and debugging)

vifm

extended-keys	Support for extended keys (arrows, home etc)
gtk	Use gtk+ to determine mimetypes
vim	Install the vifm vim plugin and vim-compatible documentation

worker

avfs	Enable support for sys-fs/avfs

yq

yq-symlink	Create a yq symlink to yq-python.

yq-go

yq-symlink	Create a yq symlink to yq-go.

app-mobilephone

gammu

curl	Enables curl support
irda	Enables infrared support
mysql	Use mysql for data storage
nls	Enable native language support
odbc	Use ODBC as DB connector
postgres	Use PostgreSQL for data storage
usb	Enable USB suport

gnokii

ical	Enable support for dev-libs/libical
irda	Enable infrared support
pcsc-lite	Enable smartcard support with sys-apps/pcsc-lite
sms	Enable SMS support (build smsd)

smstools

stats	Enable statistic reporting

app-office

abiword

collab	Enable collaborative editing plugin
goffice	Enable goffice plugin
grammar	Enable grammar checking via dev-libs/link-grammar
map	Enable world map support through media-libs/libchamplain
math	Enable support for x11-libs/gtkmathview
ots	Enable Text Summarizer plugin
plugins	Enable plugins build (see http://www.abisource.com/wiki/PluginMatrix for more information). If your file cannot be opened due lack of support, try enabling this.
redland	Enables support redland and raptor libs.
thesaurus	Enable thesaurus support
wordperfect	Enable wordperfect file support via app-text/libwpd

calcurse

caldav	Support CalDAV

calligra

charts	Build chartshape plugin for creating business charts with dev-libs/kdiagram
import-filter	Enable support for various import filter file formats like WordPerfect, Visio and Apple Keynote
lcms	Build colorengine plugins using media-libs/lcms
okular	Enable bindings for kde-apps/okular
phonon	Build stage/eventplugins and videoshape plugin using media-libs/phonon
webengine	Enable Braindump support using dev-qt/qtwebengine

calligraplan

activities	Enable kactivities support
holidays	Enable kde-frameworks/kholidays integration
kwallet	Enable access to encrypted OpenDocument files with kde-frameworks/kwallet storage

glabels

barcode	Enable barcode support through external libraries.

gnucash

aqbanking	Connect to some internet banks via AqBanking
quotes	Enable online stock quote retrieval

gnumeric

libgda	Enable database support through gnome-extra/libgda.
perl	Enable perl plugin loader.

grisbi

goffice	enable goffice graphic support

kmymoney

activities	Enable kde-plasma/plasma-activities integration
addressbook	Enable kde-apps/akonadi contact integration
hbci	Enable HBCI support using net-libs/aqbanking
holidays	Enable kde-frameworks/kholidays integration

kraft

pim	Enable support for KDE PIM resources integration

libalkimia

webengine	Enable online quotes using dev-qt/qtwebengine

libreoffice

base	Enable full support for LibreOffice Base databases (involves additional bundled libs)
clang	Use Clang compiler instead of GCC
coinmp	Use sci-libs/coinor-mp as alternative solver
googledrive	Enable support for remote files on Google Drive
mariadb	Prefer mariadb connector over mysql connector
odk	Build the Office Development Kit
pdfimport	Enable PDF import via the Poppler library
vulkan	Enable Vulkan usage via the skia library (clang recommended)

libreoffice-l10n

offlinehelp	Install help files locally instead of using the LibreOffice Wiki

lyx

aspell	Add support for aspell spellchecking
dia	Add support for diagrams (app-office/dia)
dot	Add support for DOT import (media-gfx/graphviz)
enchant	Add support for enchant spellchecking wrapper (both aspell and hunspell can be used by LyX).
gnumeric	Add support for importing Gnumeric/OpenOffice/MS Excel spreadsheets into LyX.
html	Add support for HTML import
hunspell	Add support for spellchecking based on hunspell and reuse system-wide OpenOffice dictionaries. This also enable thesaurus dictionaries not accessible via aspell.
monolithic-build	This should speed up compilation significantly when you have enough RAM (> 600 MB)
rcs	Add support for revision control via dev-vcs/rcs
rtf	Add support for RTF import/export packages

magicpoint

contrib	Install additional contributed scripts

mdbtools

glib	Use functions provided by dev-libs/glib, not built-in

planner

libgda	PostgreSQL support via gnome-extra/libgda

sc-im

X	Use x11-misc/xclip for clipboard copy/paste
ods	Add ods import support
plots	Add sci-visualization/gnuplot for plotting support
tmux	Use app-misc/tmux for clipboard copy/paste
wayland	Use gui-apps/wl-clipboard for clipboard copy/paste
xls	Add xls support
xlsx	Add xlsx support

scribus

boost	Enable support for Boost based enhancement
hunspell	Enable support for spell checking with app-text/hunspell
minimal	Don't install headers (only required for e.g. plug-in developers)
osg	3D rendering via dev-games/openscenegraph
scripts	Install the scripts
templates	Document templates
tk	Install tk based scripts e.g. FontSample.py

skrooge

activities	Enable kactivities support

texmacs

netpbm	Add support for media-libs/netpbm

texstudio

video	Enable video player in pdf files

app-pda

gtkpod

clutter	Enable clutter support for displaying coverart

app-portage

conf-update

colordiff	Use colors when displaying diffs (app-misc/colordiff)

eix

debug	Build with upstream's CXXFLAGS/LDFLAGS for debugging support; not recommended for normal use.
doc	Create description of the eix cache file additionally in html format
sqlite	Compile in support for portage's sqlite backend; to actually use it you need additional configuration of portage and eix

gemato

gpg	Install dependencies needed for OpenPGP signature verification support
pretty-log	Pull dev-python/rich to enable pretty logs
tools	Install additional utilities (benchmarks, hash testing tools, fast Manifest generators) to /usr/share/gemato.

grs

server	Install all the tools building systems

hackport

profile	Enable profiling flags

kuroneko

scraper	Include the dependencies necessary for Bugzilla scraping.

nattka

depgraph-order	Process packages in depgraph order whenever possible.

pfl

network-cron	Adds a cron job which does a weekly submit of the package database

portage-utils

qmanifest	Build qmanifest applet, this adds additional dependencies for GPG, OpenSSL and BLAKE2B hashing
qtegrity	Build qtegrity applet, this adds additional dependencies for OpenSSL

tatt

templates	Install template scripts to be used with tatt

app-shells

atuin

client	Enable the autin client
daemon	Enable the autin background daemon on the client
server	Enable the autin server
sync	Enable the server-sync feature in the autin client

autojump

ipython	Add support for dev-python/ipython

bash

bashlogger	Log ALL commands typed into bash; should ONLY be used in restricted environments such as honeypots
mem-scramble	Build with custom malloc/free overwriting allocated/freed memory
net	Enable /dev/tcp/host/port redirection
pgo	Optimize the build using Profile Guided Optimization (PGO)
plugins	Add support for loading builtins at runtime via 'enable'

bash-completion

eselect	Support blacklisting of completions via 'eselect bashcomp'. This enables custom Gentoo patching of upstream completion loader.

mksh

lksh	variant that uses POSIX-compliant arithmetics with the host “long” data type and is automatically in POSIX mode when called as /bin/sh

nushell

plugins	Build official plugins
system-clipboard	System clipboard support in `reedline`

pdsh

rsh	This allows the use of rsh (remote shell) and rcp (remote copy) for authoring websites. sftp is a much more secure protocol and is preferred.

shish

diet	Use dev-libs/dietlibc

app-text

atril

caja	Enable property page extension in mate-base/caja
dvi	Enable build-in DVI viewer
epub	Enable build-in DVI viewer using net-libs/webkit-gtk
synctex	Enable search highlighting through synctex (virtual/tex-base)
t1lib	Enable the Type-1 fonts for the build-in DVI viewer (media-libs/t1lib)
xps	Enable XPS viewer using app-text/libgxps

blogc

git	Build blogc-git-receiver tool
httpd	Build blogc-runserver tool
make	Build blogc-make tool

calibre

font-subsetting	Enable font subsetting support
system-mathjax	Use a system copy of mathjax
unrar	Enable support for comic books compressed with the non-free Rar format

cmigemo

vim	Install Vim plugin for C/Migemo

crengine-ng

chm	Support chm format
fribidi	Support bidirectional text by dev-libs/fribidi
harfbuzz	Use media-libs/harfbuzz for kerning and ligatures
libunibreak	Use dev-libs/libunibreak for hyphenation
libutf8proc	Use dev-libs/libutf8proc for manipulating unicode strings

crm114

mew	Add support for using the mewdecode mime decoder (app-emacs/mew)
normalizemime	Add support for using the normalizemime (mail-filter/normalizemime)

crqt-ng

chm	Support chm format
fribidi	Support bidirectional text by dev-libs/fribidi
harfbuzz	Use media-libs/harfbuzz for kerning and ligatures
libunibreak	Use dev-libs/libunibreak for hyphenation
libutf8proc	Use dev-libs/libutf8proc for manipulating unicode strings

crwx-ng

chm	Support chm format
fribidi	Support bidirectional text by dev-libs/fribidi
harfbuzz	Use media-libs/harfbuzz for kerning and ligatures
libunibreak	Use dev-libs/libunibreak for hyphenation
libutf8proc	Use dev-libs/libutf8proc for manipulating unicode strings

dblatex

inkscape	Use inkscape to convert SVG. Disable to use gnome-base/librsvg instead.

dictd

judy	Build Judy-based (dev-libs/judy) plugin implementing fast "exact" and especially "lev" strategies
minimal	Don't build server but dict client, dictzip and dictfmt only.

docbook-sgml-utils

jadetex	Add support for processing tex files produced by the TeX backend of Jade

docbook-xsl-ns-stylesheets

ruby	Install the Ruby-based dbtoepub script; requires an interpreter compatible with app-eselect/eselect-ruby.

docbook-xsl-stylesheets

ruby	Install the Ruby-based dbtoepub script; requires an interpreter compatible with app-eselect/eselect-ruby.

doxygen

clang	support for sys-devel/clang assisted parsing
dot	allow to create dot graphs using media-gfx/graphviz
doxysearch	build doxyindexer and doxysearch.cgi

ebook-tools

lit2epub	Install lit2epub script

editorconfig-core-c

cli	Install command line interface.

enchant

aspell	Adds support for app-text/aspell spell checker
hunspell	Adds support for app-text/hunspell spell checker
nuspell	Adds support for app-text/nuspell spell checker
voikko	Adds support for dev-libs/libvoikko spell checker

evince

dvi	Enable the built-in DVI viewer
nautilus	Enable property page extension in gnome-base/nautilus
postscript	Enable support for PostScript and Adobe Illustrator documents with app-text/libspectre
spell	Enable inline spell check for annotations via app-text/gspell
xps	Enable XPS viewer using app-text/libgxps

feathernotes

X	Link application against X11 libraries which adds support for virtual desktop awareness and tab DND

ghostscript-gpl

unicode	Add support for unicode passwords via net-dns/libidn

groonga

abort	Enable query abortion
benchmark	Build benchmark programs
dynamic-malloc-change	Allow dynamic memory allocation change for testing
exact-alloc-count	Atomic counting for memory alloc count
fmalloc	Make memory allocation failed in specified condition for debug
futex	Use futex
libevent	Enable dev-libs/libevent used for suggestion
mecab	Use app-text/mecab for morphological analysis
msgpack	Enable dev-libs/msgpack used for suggestion
nfkc	Use nfkc based utf8 normalization
sphinx	Enable document generation by app-misc/sphinx
uyield	Build for detecting race conditions
zeromq	Enable net-libs/zeromq used for suggestion

htmltidy

deprecated	Install tools and header files which are now considered deprecated

hyperestraier

mecab	Enable app-text/mecab support for Estraier

kbibtex

webengine	Use dev-qt/qtwebengine for HTML previews

lcdf-typetools

kpathsea	Enable integration with kpathsea search library (TeX related)

libebook

tools	Build file conversion tools

libgepub

webkit	Build with GepubWidget based on Webkit

libmwaw

tools	Build file conversion tools

libqxp

tools	Build file conversion tools

libstaroffice

tools	Build conversion tools
zlib	Enable support for compressed data

libwpd

tools	Build file conversion tools

libwps

tools	Build file conversion tools

mandoc

cgi	build man.cgi web plugin for viewing man pages
system-man	set as the default man provider

mathtex

png	Generate png images by default instead of gif

msort

heap	Use heap instead of alloca()
icu	Use dev-libs/icu instead of dev-libs/libutf8proc.
libuninum	Use dev-libs/libuninum for conversion.

mupdf

archive	Enable support for CBR and other archive formats using libarchive

pandoc

embed-data-files	Embed data files in binary for relocatable executable.
trypandoc	Build trypandoc cgi executable.

pandoc-bin

pandoc-symlink	Install pandoc symlink that points to pandoc-bin

pandoc-cli

lua	Support custom modifications and conversions with the pandoc Lua scripting engine.
nightly	Add '-nightly-COMPILEDATE' to the output of '--version'.
server	Include support for running pandoc as an HTTP server.

pdfgrep

unac	Removing accents and ligatures before search

pdfjam

extra	Install unsupported wrapper scripts, for example pdf90, pdfnup, pdfjoin

pdfpc

gstreamer	Compile support for movie playback (media-libs/gstreamer)
soup	Compile support for REST server (net-libs/libsoup)
webkit	Enable viewing Markdown notes (net-libs/webkit-gtk)

pelican

markdown	Markdown support

podofo

boost	Add support for boost
tools	Build and install commandline tools.

poppler

boost	Use boost::small_vector for a serious performance gain
gpgme	Enable signatures handling with app-crypt/gpgme
nss	Enable signatures handling with dev-libs/nss
utils	Install command-line PDF converters and various utilities.

qpdfview

fitz	Use experimental fitz rendering, provided by app-text/mupdf, instead of poppler
synctex	Add support for searching TeX sources

robodoc

examples	Installs usage examples in /usr/share for Perl

sdcv

darkterm	Improve readability of color output on terminals with dark background.

sigil

plugins	Installed needed Python packages for using Sigil plugins
system-mathjax	Use the system-wide dev-libs/mathjax instead of bundled

sword

clucene	Use dev-cpp/clucene for lucene search support

tessdata_best

osd	Enable support orientation and script detection.

tessdata_fast

osd	Enable support orientation and script detection.

tessdata_legacy

math	Enable support for recognition of equations.
osd	Enable support orientation and script detection.

tesseract

float32	Support float for model training and text recognition (faster, requires less RAM)
training	Install training applications to add support for new languages.

texlive

context	Add support for the ConTeXt format (dev-texlive/texlive-context)
extra	Add support for extra TeXLive packages
games	Add typesetting support for games (chess, etc.) (dev-texlive/texlive-games)
graphics	Add support for several graphics packages (pgf, tikz,...)
humanities	Add LaTeX support for the humanities (dev-texlive/texlive-humanities)
luatex	Install TeX Live packages that require luatex
metapost	Add support for metapost: A tool for creating graphics in scalable PostScript
music	Add support for music typesetting (dev-texlive/texlive-music)
pdfannotextractor	Add dev-tex/pdfannotextractor support, for extracting annotations from PDF files
pstricks	Add pstricks packages (dev-texlive/texlive-pstricks)
publishers	Add support for publishers (dev-texlive/texlive-publishers)
science	Add typesetting support for natural and computer sciences (dev-texlive/texlive-mathscience)
tex4ht	Add support for dev-tex/tex4ht (for converting (La)TeX to (X)HTML, XML and OO.org)
texi2html	Add support for app-text/texi2html which converts texi files to HTML
xetex	Add support for XeTeX macros (dev-texlive/texlive-xetex)

texlive-core

luajittex	Add support for LuaJitTeX: LuaTeX based on LuaJIT which is usually faster.
xetex	Add support for XeTeX: a TeX system with Unicode and modern font technologies.
xindy	Add support for Xindy: A general-purpose index processor.

wdiff

experimental	Build experimental utilities (mdiff, unify, wdiff2)

webgen

builder	Enable programmatic HTML/XML generation
highlight	Enable syntax highlighting for certain plugins
markdown	Markdown support

writerperfect

abiword	Add support for abiword format using app-text/libabw
ebook	Add support for various ebook formats using app-text/libebook
epub	Add support for conversion to ePub format using app-text/libepubgen
freehand	Add support for freehand format using media-libs/libfreehand
gsf	Add support for structured files using gnome-extra/libgsf
keynote	Add support for keynote format using app-text/libetonyek
mspub	Add support to mspub format using app-text/libmspub
mwaw	Add support to mwaw formats using app-text/libmwaw
pagemaker	Add support to pagemaker formats using media-libs/libpagemaker
qxp	Add support for QuarkXpress documents using app-text/libqxp
visio	Add support for visio format using media-libs/libvisio
wpd	Add support for wpd format using app-text/libwpd
wpg	Add support for wpg format using app-text/libwpg
wps	Add support for wps format using app-text/libwps
zmf	Add support for Zoner Callisto/Draw documents format using media-libs/libzmf

wv

tools	Install optional utilities considered deprecated in favor of using AbiWord.

xmlto

text	Support conversion from XML to plain text

xpdf

cmyk	Include support for CMYK rasterization
i18n	Enable support non-UTF8 national charsets
icons	Generate desktop PNG icons using rsvg-convert from gnome-base/librsvg
libpaper	Use app-text/libpaper to get paper preferences
metric	Use A4 instead of US Letter paper size by default for PostScript output. This option has effect only if libpaper USE flag is disabled
opi	Include support for OPI (Open Prepress Interface) comments
textselect	Allow text selection
utils	Install command-line PDF converters and various utilities

zathura

synctex	Use libsynctex to get latex codeline from pdf

zathura-meta

cb	Install plug-in for ComicBook support

zeal

X	Enable global shortcut support on X11

app-vim

gentoo-syntax

ignore-glep31	Remove GLEP 31 (UTF-8 file encodings) settings

app-xemacs

xemacs-packages-all

mule	Add multi-language support to XEmacs

dev-ada

AdaSAT

shared	Build shared library
static-pic	Build static library with pic code

VSS

shared	Build shared library
static-pic	Build static library with pic code

aws

shared	Build shared library
wsdl	Used to convert ada to wsdl

gnatcoll-bindings

shared	Build shared library
static-pic	Build shared library

gnatcoll-core

shared	Build shared library
static-pic	Build static library with pic code

gnatcoll-db

db2ada	Build gnatcoll_db2ada
gnatinspect	Build gnatinspect
shared	Build shared library
sql	Build sql library
static-pic	Build shared library
xref	Build xref library

gpr

shared	Build shared library
static-pic	Build static library with pic code

gpr-unit-provider

shared	Build shared library
static-pic	Build static library with pic code

gtkada

shared	Build gtkada as shared library
static-pic	Build static library with pic code

lal-refactor

shared	Build shared library
static-pic	Build static library with pic code

langkit

shared	Build shared library
static-pic	Build static library with pic code

libadalang

static-pic	Build static library with pic code

libadalang-tools

shared	Build shared library
static-pic	Build static library with pic code

libgpr

shared	Build shared library
static-pic	Build static library with pic code

spawn

glib	Add support to dev-libs/glib-based mainloop.
shared	Build shared library
static-pic	Build static library with pic code

templates-parser

shared	Build shared library

xmlada

shared	Build shared library
static-pic	Build static library with pic code

dev-build

bazelisk

bazel-symlink	Install bazel symlink that points to bazelisk

cmake

dap	Build debugger for CMake with Debug Adapter Protocol support via dev-cpp/cppdap

muon

archive	Enable extracting wraps using app-arch/libarchive.
libpkgconf	Enable looking up packages via dev-util/pkgconf.

dev-cpp

benchmark

exceptions	Enable the use of exceptions in the benchmark library
libcxx	Use sys-libs/libcxx instead of libstdc++ as the default stdlib
libpfm	Enable dev-libs/libpfm support
tools	Install some additional Python tools

eigen

adolc	Add test support for Adolc (sci-libs/adolc)
benchmark	Build benchmark suite
boost	Add test support for Boost.Multiprecision (dev-libs/boost)
cholmod	Add test support for CHOLMOD (sci-libs/cholmod)
clang	Use clang for cuda units compilation
fftw	Add test support for fftw (sci-libs/fftw)
hip	Enable HIP GPU computing support
klu	Add test support for KLU (sci-libs/klu)
mathjax	Use MathJax for rendering math in HTML docs (dev-libs/mathjax)
opengl	Add test support for OpenGL
openmp	Add test support for the OpenMP (support parallel computing)
pastix	Add test support for PaStiX (sci-libs/pastix)
sparsehash	Add test support for GoogleHash (dev-cpp/sparsehash)
spqr	Add test support for SPQR (sci-libs/spqr)
superlu	Add test support for SuperLU (sci-libs/superlu)
umfpack	Add test support for UMFPACK (sci-libs/umfpack)

glog

gflags	Use dev-cpp/gflags for flag parsing
libunwind	Use libunwind library (sys-libs/libunwind or sys-libs/llvm-libunwind) instead of built-in fallback implementation for stack unwinding

gtest

abseil	Build with functionality provided by dev-cpp/abseil-cpp and dev-libs/re2

jwt-cpp

picojson	Enable use of dev-cpp/picojson

libcmis

tools	Build client tool for testing and viewing features

libjson-rpc-cpp

http-client	Build support for HTTP client using net-misc/curl
http-server	Build support for HTTP server using net-libs/libmicrohttpd
redis-client	Build support for Redis client using dev-libs/hiredis
redis-server	Build support for Redis server using dev-libs/hiredis
stubgen	Build header stub code generator (needed for development and when pregenerated headers are not bundled)

msgpack-cxx

boost	Enable boost support

opentelemetry-cpp

jaeger	Include the jaeger exporter
prometheus	include the Prometheus Client in the SDK

sdbus-c++

systemd	Use external libsystemd instead of statically-linked build
tools	Install interface stub code generator

dev-db

etcd

server	Installs etcd daemon

firebird

server	Install the server components of Firebird, not just the client
xinetd	Install ClassicServer

mariadb

backup	Build mariadb-backup which supports SST and hot backup of InnoDB, Aria and MyISAM including compression and encryption
columnstore	Build the ColumnStore storage engine
extraengine	Add support for alternative storage engines (Archive, CSV, Blackhole, Federated(X), Partition)
galera	Enables galera replication
innodb-lz4	Enables lz4 compression methods for InnoDB/XtraDB
innodb-lzo	Enables lzo compression methods for InnoDB/XtraDB
innodb-snappy	Enables snappy compression methods for InnoDB/XtraDB using app-arch/snappy
jdbc	Enable the CONNECT engine to access foreign databases via JDBC
latin1	Use LATIN1 encoding instead of UTF8
mroonga	Add support for the Mroonga engine for interfacing with the Groonga text search
numa	Enable NUMA support using sys-process/numactl (NUMA kernel support is also required)
oqgraph	Add support for the Open Query GRAPH engine
pam	Enable the optional PAM authentication plugin for the server
profiling	Add support for statement profiling (requires USE=community).
rocksdb	Add support for RocksDB; a key/value, LSM database optimized for flash storage
s3	Build the S3 storage engine
server	Build the server program
sphinx	Add suport for the sphinx full-text search engine
sst-mariabackup	Add tools needed to support the mariabackup SST method
sst-rsync	Add tools needed to support the rsync SST method
systemtap	Build support for profiling and tracing using dev-debug/systemtap
test	Install upstream testsuites for end use.
yassl	Enable SSL connections and crypto functions using the bundled yaSSL

mongodb

mongosh	Install the MongoDB shell from app-admin/mongosh-bin
tools	Install the MongoDB tools (mongoimport, mongodump...) from app-admin/mongo-tools

mycli

ssh	Add support for connection over SSH tunnel

mysql

cjk	Add CJK support for InnoDB fulltext search using app-text/mecab
client-libs	Build the client libraries from the server package instead of the C Connector packages (not recommended)
experimental	Build experimental features aka "rapid" plugins
latin1	Use LATIN1 encoding instead of UTF8
numa	Enable NUMA support using sys-process/numactl (NUMA kernel support is also required)
profiling	Add support for statement profiling (requires USE=community).
router	Build the MySQL router program
server	Build the server program
systemtap	Build support for profiling and tracing using dev-debug/systemtap
test	Install upstream testsuites for end use.

mysql-connector-c++

legacy	Build the legacy 1.x API as well as the DevX API

oracle-instantclient

jdbc	Support for XA, Internationalization, and RowSet operations under JDBC
odbc	Libraries for enabling ODBC applications
precomp	"proc" binary and related files to precompile a Pro*C application
sdk	Header files and an example makefile for developing Oracle applications
sqlplus	The SQL*Plus command line tool for SQL and PL/SQL queries
tools	Data Pump, SQL*Loader and Workload Replay Client

percona-server

cjk	Add CJK support for InnoDB fulltext search using app-text/mecab
latin1	Use LATIN1 encoding instead of UTF8
numa	Enable NUMA support using sys-process/numactl (NUMA kernel support is also required)
profiling	Add support for statement profiling (requires USE=community).
rocksdb	Add support for RocksDB; a key/value, LSM database optimized for flash storage
router	Build the MySQL router program
server	Build the server program
tokudb	Add support for TokuDB storage engine
tokudb-backup-plugin	Builds the TokuDB backup plugin

pgbouncer

c-ares	Use c-ares as the DNS backend instead of evdns (libevent).
udns	Use udns as the DNS backend instead of evdns (libevent). Supports IPv4 only.

pgpool2

memcached	Use memcached for query caching.

phpmyadmin

setup	Installs the phpMyAdmin setup utility. Users who don't use the utility should disable this USE flag for security reasons as the setup tool was the target of various exploits in the past.

postgis

address-standardizer	Normalize US and CA postal addresses
gtk	Build graphical interface for shp2pgsql (shp2pgsql-gui)
topology	Build topology spatial types and functions

postgresql

llvm	Add support for llvm JIT engine
server	Disable to build and install the clients and libraries only.
uuid	Enable server side UUID generation (via dev-libs/ossp-uuid).

psqlodbc

iodbc	Use dev-db/libiodbc. Disable to use dev-db/unixODBC.

recutils

curl	Enable support for remote descriptors using net-misc/curl
mdb	Build the mdb2rec utility using app-office/mdbtools

redict

tcmalloc	Use tcmalloc from dev-util/google-perftools for allocations.

redis

tcmalloc	Use tcmalloc from dev-util/google-perftools for allocations.

spatialite

geos	Add the sci-libs/geos library for exact topological tests
proj	Add the sci-libs/proj library for reprojection features
rttopo	Add the sci-geosciences/librttopo library for topology support
xls	Add the dev-libs/freexl library for xls import support

sqldeveloper

sybase	Add support for the Sybase SQL Database Server

sqlite

secure-delete	Enable overwriting of deleted content with zeros by default (http://sqlite.org/pragma.html#pragma_secure_delete), causing some performance penalty
tools	Install additional tools, among which are included: sqlite3-analyzer, sqlite3-changeset, sqlite3-db-dump, sqlite3-diff, sqlite3-rbu, sqlite3-expert and others.

sqlitebrowser

sqlcipher	Allow to open and to edit databases encrypted using dev-db/sqlcipher

sqlitestudio

cli	Build CLI interface

timescaledb

proprietary-extensions	Enable proprietary features/extensions licensed under the TimeScale License

unixODBC

minimal	Disable bundled drivers and extra libraries (most users don't need these)
odbcmanual	Administrator, Internal Structure, Programmer and User documentation

dev-debug

bpftrace

fuzzing	Build bpftrace for fuzzing
lldb	Parse debug info usingdev-debug/lldb

dtrace

test-install	Install the testsuite for manual use. It is not suitable for automatic execution within the ebuild because it requires root privlieges.

gdb

cet	Enable Intel Control-flow Enforcement Technology.
debuginfod	Enable debuginfod support via dev-libs/elfutils libdebuginfod
lzma	Support lzma compression in ELF debug info
multitarget	Support all known targets in one gdb binary
python	Enable support for the new internal scripting language, as well as extended pretty printers
server	Install the "gdbserver" program (useful for embedded/remote targets)
sim	Build gdb's simulators for various hardware platforms. See https://sourceware.org/gdb/wiki/Sim.
source-highlight	Enable listing highlighting via dev-util/source-highlight
xml	Support parsing XML data files needed (at least) for cpu features, memory maps, and syscall tracing
xxhash	Use dev-libs/xxhash to speed up internal hashing.

lldb

debuginfod	Expose the transitive dependencies on net-misc/curl and dev-cpp/cpp-httplib) to match sys-devel/llvm.

ltrace

elfutils	Use libdwfl from dev-libs/elfutils for frame unwinding support
unwind	Use sys-libs/libunwind for frame unwinding support

strace

aio	Enable dev-libs/libaio support for tracing Asynchronous I/O operations
elfutils	Enable stack backtraces (-k flag) via dev-libs/elfutils
unwind	Enable stack backtraces (-k flag) via sys-libs/libunwind

sysdig

bpf	Enable the BPF probe as alternative event source to dev-debug/scap-driver.
modules	Build kernel modules needed for tracing local events. Disable this only if you intend to use sysdig purely to work with dumpfiles.

systemtap

debuginfod	Enable debuginfod support via dev-libs/elfutils libdebuginfod
dtrace-symlink	Provide /usr/bin/dtrace symlink pointing to /usr/bin/stap-dtrace. This prevents coinstallation with dev-debug/dtrace.
libvirt	Support probing of libvirt domains.

dev-embedded

avrdude

ftdi	Enable support for USB FTDI chips via dev-embedded/libftdi

libftdi

tools	build ftdi_eeprom helper tool

openocd

capstone	Use dev-libs/capstone for disassembly support
cmsis-dap	Support for CMSIS-DAP compliant adapters
dummy	Build the dummy port driver
ftdi	Enable support for USB FTDI chips via dev-embedded/libftdi
gpiod	Enable Linux GPIO bitbang support via libgpiod
jlink	Build the SEGGER J-Link driver
parport	Enable support for parport JTAG devices
verbose-io	Verbose IO and comm JTAG and USB messages

rpi-eeprom

pi4	Install firmware files for the Raspberry Pi 4
pi5	Install firmware files for the Raspberry Pi 5

sdcc

boehm-gc	Enable Hans Boehm's garbage collector dev-libs/boehm-gc
device-lib	Enable built of devices libraries
ds390	Add support for Dallas DS390
ds400	Add support for Dallas DS400
ez80-z80	Add support for EZ80-Z80
hc08	Add support for Freescale/Motorola HC08 based
mcs51	Add support for Intel mcs51
mos6502	Add support for MOS 6502
mos65c02	Add support for MOS 65C02
non-free	Enable non-free runtime library parts
packihx	Enable Intel HEX files pack utility
pdk13	Add support for PDK13
pdk14	Add support for PDK14
pdk15	Add support for PDK15
pdk16	Add support for PDK16
pic14	Add support for Microchip 14 bits PICs
pic16	Add support for Microchip 16 bits PICs
r2k	Add support for Rabbit 2000
r2ka	Add support for Rabbit 2000A
r3ka	Add support for Rabbit 3000A
s08	Add support for Freescale/Motorola S08
sdcdb	Enable SDCC source level debugger
sdcpp	Enable SDCC preprocessor based on GCC cpp
sm83	Add support for Gameboy SM83
stm8	Add support for STMicroelectronics STM8
tlcs90	Add support for TLCS-90
ucsim	Enable software simulator for microcontrollers
z180	Add support for Zilog Z180
z80	Add support for Zilog Z80
z80n	Add support for Zilog Z80N

u-boot-tools

envtools	Build only the target-side environment tools

urjtag

ftd2xx	Enable support for USB FTDI chips via dev-embedded/libftd2xx
ftdi	Enable support for USB FTDI chips via dev-embedded/libftdi

dev-games

godot

deprecated	Enable support for deprecated features
raycast	Enable the raycast Editor module using media-libs/embree
tools	Enable the Godot Editor for game development

guichan

allegro	Build the Allegro frontend

mygui

l10n_ru	Install some additional russian docs if 'doc' useflag enabled
ogre	Use the ogre render subsystem. (cannot combine with opengl)
opengl	Use the opengl render subsystem. (cannot combine with ogre)
plugins	Build MyGUI plugins
samples	Install MyGUI demos (needs ogre USE flag)
tools	Build the tools for development

ode

double-precision	more precise calculations at the expense of speed
gyroscopic	enable gyroscopic term (may cause instability)

ogre

assimp	Use media-libs/assimp to import assets from 3D files
boost	Enable boost support
bullet	Use sci-physics/bullet for physics plugin
cache	Enable GL state cache support
cg	NVIDIA toolkit plugin
deprecated	Build deprecated nodeless positioning of Lights and Cameras.
double-precision	More precise calculations at the expense of speed
egl	Use egl instead of glx
fine-granularity	Enable fine light mask granularity. This impacts on performance and should not be enabled unless an application really needs it.
freeimage	Support images via media-libs/freeimage
gl3plus	Build OpenGL 3+ RenderSystem
gles3	Enable OpenGL ES 3.x Features
json	Use dev-libs/rapidjson (needed by Hlms JSON materials)
legacy-animations	Use the skeletal animation from 1.x. It's much slower, but the new system is still experimental.
ois	Pull in Object-oriented Input System library dev-games/ois for samples
poco	When USE=threads, use poco for threading
resman-pedantic	Resource Manager PEDANTIC : require an explicit resource group. Case sensitive lookup. Some demos might not work with this setting. (default: case-insensitive + sensitive lookup in all groups)
tbb	When USE=threads, use tbb for threading
tools	Build and install AssimpConverter (assimp USE flag is enabled), MeshUpgrader, VRMLConverter and XMLConverter

openscenegraph

collada	Enable DAE file support via dev-libs/collada-dom
dicom	Enable DICOM medical image file support via sci-libs/dcmtk
fox	Build examples using x11-libs/fox library
gdal	Enable support for sci-libs/gdal library
las	Enable support for geospatial data LAS LiDAR format using sci-geosciences/liblas
openinventor	Build OpenInventor plugin
osgapps	Build osg applications
sdl2	Use media-libs/libsdl2 additionally to media-libs/libsdl
xrandr	Enable support for the X xrandr extension

openscenegraph-openmw

collada	Enable DAE file support via dev-libs/collada-dom
dicom	Enable DICOM medical image file support via sci-libs/dcmtk
fox	Build examples using x11-libs/fox library
gdal	Enable support for sci-libs/gdal library
las	Enable support for geospatial data LAS LiDAR format using sci-geosciences/liblas
openinventor	Build OpenInventor plugin
osgapps	Build osg applications
sdl2	Use media-libs/libsdl2 additionally to media-libs/libsdl
xrandr	Enable support for the X xrandr extension

physfs

7zip	Enable 7zip/lzma archive support
grp	Enable Build Engine GRP archive support
hog	Enable Descent I/II HOG archive support
iso	Enable ISO9660 file support
mvl	Enable Descent I/II MVL archive support
qpak	Enable Quake I/II QPAK archive support
slb	Enable Independence War SLB archive support
vdf	Enable Gothic/Gothic II VDF archive support
wad	Enable Doom WAD archive support

simgear

dns	Enable DNS resolver via net-libs/udns
gdal	Enable alternative terrain engine based on pagedLOD via sci-libs/gdal
subversion	Enable terrasync scenery downloader

tiled

minimal	Exclude optional plugins and development headers

dev-gap

grape

bliss	Use sci-libs/bliss instead of sci-mathematics/nauty as the backend.

dev-haskell

abstract-deque

usecas	Enable the reference implementation to use hardware compare-and-swap.

aeson

cffi	Controls whether to include c-ffi bits or pure haskell. Default to False for security.
ordered-keymap	Use ordered @Data.Map.Strict@ for KeyMap implementation.

aeson-pretty

executable	build/install the command-line tool as well as the library
lib-only	don't build 'aeson-pretty' executable.

ansi-terminal

example	Build the example application

assoc

tagged	You can disable the use of the `tagged` package using `-f-tagged`. Disabing this is an unsupported configuration, but it may be useful for accelerating builds in sandboxes for expert users.

atomic-primops

debug	Enable extra internal checks.

bifunctors

semigroups	You can disable the use of the `semigroups` package using `-f-semigroups`. Disabing this is an unsupported configuration, but it may be useful for accelerating builds in sandboxes for expert users.
tagged	You can disable the use of the `tagged` package using `-f-tagged`. Disabing this is an unsupported configuration, but it may be useful for accelerating builds in sandboxes for expert users.

bitvec

gmp	Link against the GMP library for the ultimate performance of `zipBits`, `invertBits` and `countBits`. Users are strongly encouraged to enable this flag whenever possible.

boring

tagged	You can disable the use of the `tagged` package using `-f-tagged`. Disabling this is an unsupported configuration, but it may be useful for accelerating builds in sandboxes for expert users.

c2hs

regression	Enable regression suite build.

cabal-install

lukko	Use @lukko@ for file-locking
native-dns	Enable use of the [resolv](https://hackage.haskell.org/package/resolv) & [windns](https://hackage.haskell.org/package/windns) packages for performing DNS lookups

cairo

svg	Build the Scalable Vector Graphics (SVG) backend of Cairo.

chell

color-output	use colors in program output

citeproc

executable	Build citeproc executable
icu	Use Haskell bindings to the ICU library

cmdargs

examples	Build the cmdargs-demo program
quotation	Build the Quote module
testprog	Build the test program

comonad

indexed-traversable	You can disable the use of the `indexed-traversable` package using `-f-indexed-traversable`. Disabling this is an unsupported configuration, but it may be useful for accelerating builds in sandboxes for expert users. If disabled we will not supply instances of `FunctorWithIndex`

contravariant

semigroups	You can disable the use of the `semigroups` package using `-f-semigroups`. Disabling this is an unsupported configuration, but it may be useful for accelerating builds in sandboxes for expert users.
statevar	You can disable the use of the `StateVar` package using `-f-StateVar`. Disabling this is an unsupported configuration, but it may be useful for accelerating builds in sandboxes for expert users.
tagged	You can disable the use of the `tagged` package on older versons of GHC using `-f-tagged`. Disabling this is an unsupported configuration, but it may be useful for accelerating builds in sandboxes for expert users.

criterion

embed-data-files	Embed the data files in the binary for a relocatable executable. (Warning: This will increase the executabl size significantly.)

crypto-api

all-cpolys	Build all the CMAC polynomes up to 10000 bits instead of just the usual ones

cryptohash-sha256

executable	Build the cryptohash-sha256sum executable

crypton

check-alignment	extra check on alignment in C layers, which cause lowlevel assert errors. for debugging only.
integer-gmp	Whether or not to use GMP for some functions
old-toolchain-inliner	use -fgnu89-inline to workaround an old compiler / linker / glibc issue.
support-aesni	allow compilation with AESNI on system and architecture that supports it
support-deepseq	add deepseq instances for cryptographic types
support-pclmuldq	Allow compilation with pclmuldq on architecture that supports it
support-rdrand	allow compilation with RDRAND on system and architecture that supports it
support-sse	Use SSE optimized version of (BLAKE2, ARGON2)
target-attributes	use GCC / clang function attributes instead of global target options.

cryptonite

integer-gmp	Whether or not to use GMP for some functions
target-attributes	use GCC / clang function attributes instead of global target options.

dlist

werror	Enable -Werror

doctest-driver-gen

executable	Build the doctest-driver-gen executable

entropy

donotgetentropy	Avoid use of the getentropy() *nix function. By default getentropy will be used if detected during compilation (this plays poorly with cross compilation).
halvm	Build for the HaLVM.

foldable1-classes-compat

tagged	You can disable the use of the `tagged` package using `-f-tagged`. Disabling this is an unsupported configuration, but it may be useful for accelerating builds in sandboxes for expert users.

foundation

experimental	Enable building experimental features, known as highly unstable or without good support cross-platform

glib

closure-signals	Use the the GClosure-based signals implementation.

gtk2hs-buildtools

closuresignals	Use the the GClosure-based signals implementation.

hackage-security

lukko	Use @lukko@ for file-locking, otherwise use @GHC.IO.Handle.Lock@

hashable

random-initial-seed	Randomly initialize the seed on every executable invocation. This is not a security feature and is intended only for testing (it can affect legitimate use cases).

hashtables

bounds-checking	if on, use bounds-checking array accesses
detailed-profiling	add detailed profiling information to profiled build-depends

haskeline

terminfo	Use the terminfo package for POSIX consoles.

hdbc-sqlite3

splitbase	Choose the new smaller, split-up package.

hslua-cli

executable	Compile `hslua` standalone executable.

hslua-repl

executable	Compile `luarepl` standalone executable.

hsyaml

exe	Enable @exe:yaml-test@ component

http-api-data

text-show	Use text-show library for efficient ToHttpApiData implementations.

httpd-shed

buildexamples	Build example executables.

juicypixels

mmap	Enable the file loading via mmap (memory map)

libyaml

system-libyaml	Use the system-wide libyaml instead of the bundled copy
unicode	Enable unicode output. Otherwise, unicode characters will be escaped.

lpeg

rely-on-shared-lpeg-library	Do not build lpeg from source, but trust that lpeg is made available in other ways, e.g., through a system-wide installation. The loader will be replaced with a placeholder function that only emits a message.

lua

system-lua	Use @pkg-config@ to discover library and include paths. Setting this flag implies `pkg-config`.

markdown-unlit

executable	Build executable

monad-logger

template-haskell	Enable Template Haskell support

monad-par

chaselev	Use Chase-Lev Deques for higher-perf work-stealing.

nats

binary	enable binary instances
hashable	enable hashable instances
template-haskell	enable template_haskell

network

devel	using tests for developers

nothunks

bytestring	Provide instances for bytestring
text	Provide instances for text
vector	Provide instances for vector

pandoc

embed-data-files	Embed data files in binary for relocatable executable.

parsec-numbers

parsec1	use dev-haskell/parsec1 instead of dev-haskell/parsec

parsers

attoparsec	You can disable the use of the `attoparsec` package using `-f-attoparsec`.
binary	You can disable the use of the `binary` package using `-f-binary`.
parsec	You can disable the use of the `parsec` package using `-f-parsec`.

persistent-sqlite

build-sanity-exe	Build a sanity check test executable

prettyprinter

buildreadme	Build the readme generator
text	While it's a core value of @prettyprinter@ to use @Text@, there are rare circumstances (mostly when @prettyprinter@ arises as a dependency of test suites of packages like @bytestring@ or @text@ themselves) when this is inconvenient. In this case one can disable this flag, so that @prettyprinter@ fallbacks to @String@.

quickcheck

template-haskell	Build Test.QuickCheck.All, which uses Template Haskell.

quickcheck-classes

aeson	You can disable the use of the `aeson` package using `-f-aeson`. This may be useful for accelerating builds in sandboxes for expert users.
binary-laws	Include infrastructure for testing class laws of binary type constructors. It is required that this flag match the value that the `unary-laws` flag was given when building `quickcheck-classes-base`. Disabling `unary-laws` while keeping `binary-laws` enabled is an unsupported configuration.
semigroupoids	You can disable the use of the `semigroupoids` package using `-f-semigroupoids`. This may be useful for accelerating builds in sandboxes for expert users.
semirings	You can disable the use of the `semirings` package using `-f-semirings`. This may be useful for accelerating builds in sandboxes for expert users.
unary-laws	Include infrastructure for testing class laws of unary type constructors. It is required that this flag match the value that the `unary-laws` flag was given when building `quickcheck-classes-base`.
vector	You can disable the use of the `vector` package using `-f-vector`. This may be useful for accelerating builds in sandboxes for expert users.

quickcheck-classes-base

binary-laws	Include infrastructure for testing class laws of binary type constructors. Disabling `unary-laws` while keeping `binary-laws` enabled is an unsupported configuration.
unary-laws	Include infrastructure for testing class laws of unary type constructors.

random-bytestring

pcg	compile with support for PCG from pcg-random

sandi

conduit	Build with conduit

semialign

semigroupoids	Build with semigroupoids dependency

sha

exe	Build a sha1 and a sha384 executable similar to 'md5sum'.

shelly

lifted	run the tests against Shelly.Lifted

simple-sendfile

allow-bsd	Allow use of BSD sendfile (disable on GNU/kFreeBSD)

skein

big-endian	When manually selecting the endianness, use big-endian (default is little-endian).
force-endianness	Use a manually selected endian when compiling (see flag 'big-endian').
reference	Use the reference implementation instead of the optimized one.

skylighting

executable	Whether to build the skylighting program

skylighting-core

executable	Build skylighting-extract tool

some

newtype-unsafe	Use implementation using @newtype@ and unsafe @Any@, instead of GADT

splitmix

optimised-mixer	Use JavaScript for mix32

tasty

clock	Depend on the clock package for more accurate time measurement

texmath

executable	Compile test executable.
server	Compile webserver.

text-short

debug	Enable runtime-checks via 'assert'

tls

compat	Accept SSLv2 client hello for beginning SSLv3 / TLS handshake
network	Use the base network library

transformers-base

orphaninstances	Build instances for orphan datatypes.

typst

executable	Compile executable to be used in testing and development.

unicode-collation

doctests	Run doctests as part of test suite. Use with: @--write-ghc-environment-files=always@.
executable	Build the unicode-collate executable.

unix-compat

old-time	build against old-time package

vector

boundschecks	Enable bounds checking
internalchecks	Enable internal consistency checks at the cost of a significant performance penalty
unsafechecks	Enable bounds checking in unsafe operations at the cost of a significant performance penalty

vector-algorithms

bench	Build a benchmarking program to test vector-algorithms performance
boundschecks	Enable bounds checking
internalchecks	Enable internal consistency checks at the cost of a significant performance penalty.
properties	Enable the quickcheck tests
unsafechecks	Enable bounds checking in unsafe operations at the cost of a significant performance penalty.

void

safe	dissable effective but unsafe coersions

wai-app-static

print	print debug info.

warp

allow-sendfilefd	Allow use of sendfileFd (not available on GNU/kFreeBSD)
x509	Adds a dependency on the x509 library to enable getting TLS client certificates.

wcwidth

cli	Enable command line tool

yaml

executable	Install the yaml2json and json2yaml executables

yesod-form

network-uri	Get Network.URI from the network-uri package

zip-archive

executable	Build the Zip executable.

zlib

bundled-c-zlib	Use the bundled zlib C sources. Requires pkg-config to be False. For windows, this is the default.
non-blocking-ffi	The (de)compression calls can sometimes take a long time, which prevents other Haskell threads running. Enabling this flag avoids this unfairness, but with greater overall cost.

dev-java

ant

antlr	Enable ANTLR Ant tasks
bcel	Enable bcel (bytecode manipulation) Ant tasks
bsf	Enable support for Apache Bean Scripting Framework (dev-java/bsf)
commonslogging	Enable commons-logging Ant tasks
commonsnet	Enable commons-net Ant tasks
imageio	Enable imageio Ant tasks
jai	Enable JAI (Java Imaging) Ant task
jakartamail	Enable Jakartamail Ant task
javamail	Enable JavaMail Ant task
jdepend	Enable Jdepend Ant tasks
jmf	Enable JMF (Java Media Framework) Ant tasks
jsch	Disable Jsch (ssh, scp and related) Ant tasks
junit	Enable JUnit Ant tasks
junit4	Enable JUnit4 Ant tasks
junitlauncher	Enable JUnit5 Ant tasks
log4j	Enable Apache log4j Ant tasks
oro	Enable Apache Oro Ant tasks
regexp	Enable Apache Regexp Ant tasks
resolver	Enable Apache Resolver Ant tasks
swing	Enable Swing Ant tasks
testutil	Enable optional test util classes
xalan	Enable Apache Xalan2 Ant tasks
xz	Enable XZ Ant tasks

commons-logging

log4j	Add optional support for log4j

dom4j

jaxen	Includes org.jaxen.dom4j package

emma

launcher	Install /usr/bin/emma. Collides with sci-biology/emboss.

java-config

compat	Install bin/java-config-2 symlink pointing to java-config

javacup

ant-task	Build and register the ant-task

jaxen

dom4j	Includes org.jaxen.dom4j package
jdom	Includes org.jaxen.jdom package
xom	Includes org.jaxen.xom package

jflex

ant-task	Build and register the ant-task

junit

migration-support	Include the junit-jupiter-migrationsupport module, which helps with migration from JUnit 4 to JUnit Jupiter
suite	Include the JUnit Platform Suite Engine, which adds test suite support
vintage	Include JUnit Vintage, which allows JUnit 5 to run JUnit 3 and JUnit 4 tests

openjdk

headless-awt	Don't install the X backend for AWT, needed by some GUIs
javafx	Import OpenJFX modules at build time, via dev-java/openjfx
jbootstrap	Build OpenJDK twice, the second time using the result of the first
source	Install JVM sources
system-bootstrap	Bootstrap using installed openjdk
systemtap	Enable SystemTap/DTrace tracing

openjdk-bin

headless-awt	Don't install the X backend for AWT, needed by some GUIs (used to be X flag)
source	Install JVM sources

openjdk-jre-bin

headless-awt	Don't install the X backend for AWT, needed by some GUIs (used to be X flag)

openjfx

media	Compile media module, based on gstreamer-minimal (does not pull gstreamer)
source	Install JavaFX sources

pdfbox

tools	Build and install pdfbox-tools

protobuf-java

system-protoc	Use protoc provided by dev-libs/protobuf

qdox

ant-task	Build the ant-task

rxtx

lfd	Installs and uses LockFileServer daemon (lfd)

saxon

ant-task	BUILD and register the ant-task

sbt

binary	Install from (Gentoo-compiled) binary instead of building from sources. Set this when you run out of memory during build.

dev-lang

R

libdeflate	Use app-arch/libdeflate rather than sys-libs/zlib for lazy-loaded R objects.

algol68g

mpfr	Add support for multiprecision floating point rouding

ammonite-repl-bin

scala2-13	Install Ammonite for Scala 2.13
scala3-0	Install Ammonite for Scala 3.0
scala3-1	Install Ammonite for Scala 3.1
scala3-2	Install Ammonite for Scala 3.2

bas

lr0	Use the LR0 parser instead of the recursive descending parser

crystal

debug	Build each module as a separate object file. Speeds build up.

erlang

kpoll	Enable kernel polling support

gdl

eigen	Build matrix manipulation with dev-cpp/eigen
glpk	Use GNU Linear Programming Kit sci-mathematics/glpk
gshhs	Add support for projection adn continent maps with sci-geosciences/gshhs-data
hdf	Add support for the Hierarchical Data Format v.4
proj	Add support for sci-libs/proj (geographic projections)
shapelib	Add support for manipulating ESRI Shapefiles with sci-libs/shapelib
udunits	Add support for manipulating units of physical quantities

gforth

check	Enable build-time sanity check.

ghc

binary	Install the binary version directly, rather than using it to build the source version.
elfutils	Enable DWARF-based backtraces using dev-libs/elfutils.
ghcbootstrap	Internal: Bootstrap GHC from an existing GHC installation.
ghcmakebinary	Internal: Build binary friendly for redistribution.
gmp	Use dev-libs/gmp for integer operations (works faster, but an external depend).
llvm	Pull in dependencies for the sys-devel/llvm codegen backend.
numa	Enable NUMA thread balancing policy using sys-process/numactl.
unregisterised	Create an unregisterised build in which only the C codegen backend will be available.

gnat-gpl

ada	Build the ADA language (GNAT) frontend
cet	Enable support for Intel Control Flow Enforcement Technology (CET)
d	Enable support for the D programming language
default-stack-clash-protection	Build packages with stack clash protection on by default
default-znow	Request full relocation on start from ld.so by default
fixed-point	Enable fixed-point arithmetic support for MIPS targets in gcc (Warning: significantly increases compile time!)
go	Build the GCC Go language frontend.
graphite	Add support for the framework for loop optimizations based on a polyhedral intermediate representation
libssp	Build SSP support into a dedicated library rather than use the code in the C library (DO NOT ENABLE THIS IF YOU DON'T KNOW WHAT IT DOES)
modula2	Build the GCC Modula-2 language frontend.
objc	Build support for the Objective C code language
objc++	Build support for the Objective C++ language
objc-gc	Build support for the Objective C code language Garbage Collector
pgo	Build GCC using Profile Guided Optimization (PGO)
rust	Build support for the Rust language, installs gccrs.
sanitize	Build support for various sanitizer functions (ASAN/TSAN/etc...)
ssp	Build packages with stack smashing protector on by default
system-bootstrap	Bootstrap using installed Ada compiler
systemtap	enable systemtap static probe points
vtv	Build support for virtual table verification (a C++ hardening feature)

gnucobol

json	Enable support for JSON template formatting via dev-libs/json-c

idris2

chez	build using dev-scheme/chez
racket	build using dev-scheme/racket
test-full	pull in depedndencies to run all tests

inform

tools	Install blorbtools for manipulating Blorb files

ispc

gpu	Enable Level0 GPU support in ispcrt.
openmp	Build with OpenMP task model (otherwise, TBB task model is used).

janet

static-libs	install janet static library archive, you must enable this flag for using `jpm build`

jerryscript

debugger	Install jerry-debugger

jsonnet

custom-optimization	Build with user-specified compiler optimizations (-Os, -O0, -O1, -O2, -O3) from CFLAGS (unsupported)

lazarus

extras	Build a lot of extra packages, including lhelp chm viewer program.
gtk2	Use gtk:2 for widgets.
gui	Build GUI IDE.
minimal	Don't build extra packages from the bigide component

logtalk

fop	Support for generating pdf documentation using fop
xslt	Support for generating html documentation using xslt

lua

deprecated	make deprecated data structures/routines available

luajit

lua52compat	Enable some upwards-compatible features from Lua 5.2 that are unlikely to break existing code.

mercury

trail	Support Mercury trail grades

mercury-extras

tommath	Enable support for tommath library

mlton

binary	install a binary version
bootstrap-smlnj	Boostrap mlton with dev-lang/smlnj (takes a long time)
pax-kernel	Enable if the user plans to run the package under a pax enabled hardened kernel
stage3	After bootstrap building mlton with dev-lang/smlnj, rebuild mlton with the second stage build of mlton (recommended).

moarvm

asan	Enable clang's Address Sanitizer functionality. Expect longer compile time.
clang	Use clang compiler instead of GCC
jit	Enable Just-In-Time-Compiler. Has no effect except on AMD64 and Darwin.
optimize	Enable optimization via CFLAGS
ubsan	Enable clang's Undefined Behavior Sanitizer functionality. Expect longer compile time.

mono

pax-kernel	Enable if the user plans to run the package under a pax enabled hardened kernel
xen	Make mono generate code that is considerably faster on xen VMs but slightly slower on for normal systems.

neko

apache	Build Apache modules

nim

test-js	Enable tests that require Node.js

nqp

clang	Toggle usage of the clang compiler in conjunction with MoarVM
moar	Build the MoarVM backend (experimental/broken)

ocaml

flambda	Enables the Flambda optimizer: A new intermediate representation (introduced in ocaml 4.03) in the depths of the compiler designed to allow for better inlining.
spacetime	Enables the Spacetime memory profiler. See https://caml.inria.fr/pub/docs/manual-ocaml/spacetime.html for more information.

php

apparmor	Support FPM application confinement through sys-libs/libapparmor
argon2	Enable password hashing algorithm from app-crypt/argon2
bcmath	Enable the BCMath Arbitrary Precision Mathematics extension
capstone	Support opcache JIT disassembly through dev-libs/capstone
cli	Enable the Command-Line Interface (CLI) SAPI
coverage	Include gcov symbols for test coverage and lcov reports. Only useful for extension developers, and requires GCC.
ctype	Enable the Character type checking (ctype) extension
embed	Enable embed SAPI
enchant	Enable the Enchant spelling library extension using app-text/enchant
ffi	Enable the Foreign Function Interface (FFI) extension using dev-libs/libffi
fileinfo	Enable the File Information extension
filter	Enable the Data Filtering extension
flatfile	Add dbm support for flat files
fpm	Enable the FastCGI Process Manager SAPI
gd	Enable the Image Processing and GD extension (requires media-libs/libjpeg-turbo and media-libs/libpng)
inifile	Add dbm support for .ini files
intl	Enables the intl extension for extended internalization support
ipv6	Support IPv6 connectivity in fopen and friends, and v6 address conversions in functions like inet_pton and inet_ntop.
jit	Enable PCRE JIT support
ldap-sasl	Add SASL support for the PHP LDAP extension using dev-libs/cyrus-sasl
lmdb	Enable support for dev-db/lmdb db backend
opcache	Enables built-in opcode cache, replacing pecl-apc et al.
opcache-jit	Enable Just In Time (JIT) compilation within the opcache extension
pcntl	Enable the Process Control extension
pdo	Enable the PHP Data Objects extension
phar	Enables the phar extension to provide phar archive support
phpdbg	Enable the PHP Debug Command Line SAPI (like gdb for php)
session-mm	Include dev-libs/mm support for session storage
sharedmem	Enable the shmop extension
simplexml	Enable the SimpleXML extension
sodium	Enable support for crypto through dev-libs/libsodium
sysvipc	Enable the PHP System-V semaphore, shared memory and IPC extension
tokenizer	Add support for the PHP file parser
tokyocabinet	Enable support for dev-db/tokyocabinet db backend
xmlreader	Enable the XMLReader extension
xmlwriter	Enable the XMLWriter extension
xslt	Build the XSL extension

polyml

portable	Build the portable interpreter version of Poly/ML instead of native

pypy

ensurepip	Install the ensurepip module that uses bundled wheels to bootstrap pip and setuptools (if disabled, it will be only possible to use venv `--without-pip`)
full-stdlib	Install complete stdlib as necessary to use PyPy for general purpose programs. By default, only a limited subset that is used when building PyPy3 executables is installed. Note that PyPy2.7's stdlib contains multiple known vulnerabilities.
symlink	Install "pypy3" symlink, making this PyPy slot the default PyPy3 implementation that is used for building Gentoo packages.
test-install	Install the test suite packages, that are required to run tests in a few reverse dependencies.

python

bluetooth	Build Bluetooth protocol support in socket module
ensurepip	Install the ensurepip module that uses bundled wheels to bootstrap pip and setuptools (if disabled, it will be only possible to use venv `--without-pip`)
jit	Enable experimental Just-In-Time compilation support.
libedit	Link readline extension against dev-libs/libedit instead of sys-libs/readline
pgo	Optimize the build using Profile Guided Optimization (PGO) by running Python's test suite and collecting statistics based on its performance. This will take longer to build.
valgrind	Disable pymalloc when running under dev-debug/valgrind is detected (may incur minor performance penalty even when valgrind is not used)
wininst	Install Windows executables required to create an executable installer for MS Windows

python-exec

native-symlinks	Install generic symlinks like python and python3. If this flag is disabled, only versioned python3.X executables will be available to end users and ebuilds not using python eclasses.

qu-prolog

pedro	Pedro subscription/notification communications system

rakudo

clang	Use Clang to compile the MoarVM backend
moar	Use the MoarVM as backend

ruby

rdoc	Install dev-ruby/rdoc after installing Ruby.
systemtap	Enable SystemTap/DTrace tracing

rust

clippy	Install clippy, Rust code linter
dist	Install dist tarballs (used for bootstrapping)
miri	Install miri, an interpreter for Rust's mid-level intermediate representation (requires USE=nightly, sometimes is broken)
nightly	Enable nightly (UNSTABLE) features (NOTE: it does not install nightly version, just enables features marked as nightly at time of release)
parallel-compiler	Build a multi-threaded rustc (experimental, not tested by upstream)
profiler	Build the profiler runtime and rust-demangler tool (needed for '-C profile-generate' or '-C instrument-coverage' codegen opts)
rust-analyzer	Install rust-analyzer, A Rust compiler front-end for IDEs (language server)
rust-src	Install rust-src, needed by developer tools and for build-std (cross)
rustfmt	Install rustfmt, Rust code formatter
system-bootstrap	Bootstrap using installed rust compiler
system-llvm	Use the system LLVM installation
wasm	Build support for the wasm32-unknown-unknown target

rust-bin

clippy	Install clippy, Rust code linter
profiler	Build the profiler runtime and rust-demangler tool (needed for '-C profile-generate' or '-C instrument-coverage' codegen opts)
rust-analyzer	Install rust-analyzer, A Rust compiler front-end for IDEs (language server)
rust-src	Install rust-src, needed by developer tools and for build-std (cross)
rustfmt	Install rustfmt, Rust code formatter

souffle

ffi	Support c++ functors with arbitrary number of arguments
swig	Enable SWIG usage, needed for Java and Python bindings

spidermonkey

clang	Use Clang compiler instead of GCC
debug	Enable assertions to allow for easier debugging of programs that link to spidermonkey -- note this will often crash software on regular end-user systems

swi-prolog

archive	Use libarchive for extension packs
cli	Add support for CLI interfaces based on readline and libedit
ipc	Add support for TIPC inter-process communication
pgo	Optimize the build using Profile Guided Optimization (PGO)
yaml	Use libyaml for YAML pack

swig

ccache	build ccache-swig(a fast compiler cache)

vala

valadoc	Installs valadoc documentation generation tool

xsb

mariadb	Enable support for the mariadb database backend

yap

R	Enable support for connecting R to Prolog
raptor	Enable support for Raptor RDF syntax libarary

zig

llvm	Build with LLVM backend and extensions enabled.

dev-libs

aml

examples	Build and install examples

antlr-c

debugger	Compiles debug info into the library

apache-arrow

compute	Build the Arrow Compute Modules
dataset	Build the Arrow Dataset Modules
json	Enables read/write json format
parquet	Enables read/write parquet data format
re2	Build with support for regular expressions using the re2 library

appstream

apt	Enables Debians APT support

appstream-glib

fonts	Enable fonts support for appstream-builder.
stemmer	Add word stemming via dev-libs/snowball-stemmer.

apr

old-kernel	Enable compatibility with older kernels
urandom	Use /dev/urandom instead of /dev/random

apr-util

nss	Install apr_crypto_nss module
openssl	Install apr_crypto_openssl module

atcore

gui	Build test GUI

bitset

tcmalloc	Use tcmalloc from dev-util/google-perftools for allocations

boehm-gc

large	optimize for large heap size (also increases max root sets)

boost

context	Build and install the Boost.Context (and Boost.Fiber) library and all other Boost libraries that depend on it
debug	Build and install only the debug version of the Boost libraries. Only enable this flag if you're developing against boost.
doc	Install the full API documentation documentation. This takes over 200MB of extra disk space.
nls	Build libboost_locale. This library requires compatible C library interfaces, which might not be provided by uClibc or other embedded libraries.
numpy	Optionally build NumPy extensions when Boost.Python is enabled
stacktrace	Build the full Boost.Stacktrace dynamic library instead of relying on the header-only implementation
tools	Build and install the boost tools (bcp, quickbook, inspect, wave)

botan

boost	Use dev-libs/boost
tools	Install optional tools for e.g. hashing

check

subunit	Enable support for the subunit unit test protocol

cyberjack

tools	Build and install optional management tools.

cyrus-sasl

authdaemond	Add Courier-IMAP authdaemond unix socket support (net-mail/courier-imap, mail-mta/courier)
ldapdb	Enable ldapdb plugin
openldap	Add ldap support for saslauthd
sample	Enable sample client and server
srp	Enable SRP authentication
urandom	Use /dev/urandom instead of /dev/random

date

only-c-locale	Build only the C locale

dbus-c++

ecore	Use Ecore integration
glib	Use glib integration

eekboard

libcanberra	Enable support for media-libs/libcanberra
xtest	Enable support for x11-libs/libXtst

efl

bmp	Enable WBMP image loader
dds	Enable DDS image loader
drm	Enable DRM engine
eet	Enable Eet image loader
efl-one	Combine multiple core libraries into one libefl.so
fribidi	Enable bidirectional text support
glib	Enable dev-libs/glib support
harfbuzz	Enable complex text shaping and layout support
hyphen	Enable text hyphenation support
ibus	Enable Intelligent Input Bus
ico	Enable Ico image loader
json	Enable lottie animation support
mono	Enable mono bindings
physics	Enable Bullet physics effects and support
pmaps	Enable PMAPS image loader
psd	Enable PSD image loader
scim	Enable Smart Common Input Method
system-lz4	Use system liblz4 instead of bundled one
tga	Enable Tga image loader
tgv	Enable Tgv image loader
tslib	Enable x11-libs/tslib for touchscreen events
unwind	Enable debug support via sys-libs/libunwind
xcf	Enable XCF image loader
xim	Enable X Input Method
xpresent	Enable x11-libs/libXpresent support

elfutils

debuginfod	Enable debuginfod support, both the debuginfod server and the libdebuginfod client library
lzma	Support automatic decompression of LZMA-compressed files and kernel images
stacktrace	Build experimental eu-stacktrace tool. Relies on integration with dev-util/sysprof. See https://developers.redhat.com/articles/2024/06/11/get-system-wide-profiles-binaries-without-frame-pointers.
utils	Install command-line utilities (all the eu-* programs)

fcgi

html	Install HTML documentation

folks

telepathy	Load contacts from the Telepathy framework
utils	Build the folks-inspect utility

fstrm

utils	Build fstrm utility programs

gf2x

custom-tune	Extra long compile time for tuning hardware specific low-level routines
fft	Build an FFT API for multiplication of 2 polynomials over GF(2)

gjs

sysprof	Enable profiling data capture support using dev-util/sysprof-capture

glib

dbus	Enable dependencies required by glib libraries using dbus service to manage settings saving
elf	Enable support for listing and extracting from ELF resource files with gresource tool
introspection	Enable generating introspection data (requires dev-libs/gobject-introspection )
mime	Pull in shared MIME database that many glib-based applications require at runtime to detect or open files. Warning: do not disable this flag unless installing on a headless server.
sysprof	Enable profiling data capture support using dev-util/sysprof-capture
systemtap	Build support for profiling and tracing using dev-debug/systemtap
utils	Install gtester-report utility to generate test report files for your software; build gresource utility with ELF support.

gmime

smime	Enable experimental S/MIME support

gmp

cpudetection

Enables runtime CPU detection (useful for binpkgs, compatibility on other CPUs). This only works on amd64/x86 at present. If this flag is enabled, GMP will work on a variety of amd64/x86 CPUs and load accelerated routines for use at runtime depending on the CPU in use. This makes it suitable for binary packages (binpkgs). If this flag is disabled, GMP will be tuned for the CPU being used at build-time and may not be usable on other machines.

pic

Force static libraries to be built as PIC to avoid TEXTRELs.

gobject-introspection

doctool	Install g-ir-doc-tool for generating documentation from introspected data

hiredict

shim	Install header shims for the hiredis api.

imath

large-stack	Enables code to take advantage of large stack support

input-pad

eekboard	Enable support for dev-libs/eekboard
xtest	Enable support for x11-libs/libXtst

intel-compute-runtime

l0	Install the oneAPI Level Zero driver alongside the OpenCL one
vaapi	Support the sharing of surfaces with Video Acceleration API (OpenCL Extension #36)

jemalloc

lazy-lock	Enable lazy locking (only lock when multi-threaded)
prof	Enable allocation profiling
stats	Enable statistics calculation/reporting
xmalloc	Add support for xmalloc (abort-on-out-of-memory)

json-glib

nls	Enable native language support (translations)

ktextaddons

designer	Build plugins for dev-qt/designer

libbase58

tools	Build command line base58 tool

libbytesize

tools	Build bscalc python CLI tool

libcdio

minimal	Only build the libcdio library and little more, just to be used to link against from multimedia players. With this USE flag enabled, none of the command-line utilities are built, nor is the CDDA library.

libcec

cubox	Enable support for enable support for the TDA995x
exynos	Enable support for Exynos chipsets
kernel-cec	Enable support for Linux kernel CEC framework
raspberry-pi	Enable support for the Raspberry Pi
tools	Enable build of cec-client and other test and demo executable tools
udev	Enable detection of USB-CEC port by udev
xrandr	Enable detection of active HDMI using xrandr extensions

libcgroup

daemon	Install the configuration tools and init/config files.
tools	Install the cgroup rules processing daemon and init/config files.

libclc

spirv	Build SPIRV targets

libdbusmenu

gtk	Enable support for GTK+2
gtk3	Enable support for GTK+3

libdex

eventfd	Allow use of eventfd
liburing	Allow use of liburing (io_uring)sys-libs/liburing
sysprof	Enable profiling data capture support using dev-util/sysprof-capture

libevent

clock-gettime	Disable use of clock_gettime even if it is available
debug	Support for running in debug mode
malloc-replacement	Support for replacing the memory management functions
mbedtls	Support for net-libs/mbedtls encryption
ssl	Support for dev-libs/openssl encryption
verbose-debug	Support for verbose debug logging

libffi

exec-static-trampoline	Don't rely on dynamic code generation for trampolines.
pax-kernel	Use PaX emulated trampolines, for we can't use PROT_EXEC

libffi-compat

pax-kernel	Use PaX emulated trampolines, for we can't use PROT_EXEC

libfido2

nfc	Enable experimental NFC support

libflatarray

cuda	Enables plugins for NVIDIA GPUs (e.g. CUDAAllocator)

libgcrypt

getentropy	Use getentropy function to obtain randomness from the kernel

libgdata

crypt	Use app-crypt/gcr for keeping tokens and passwords in non-pageable memory for improved security
gnome-online-accounts	Enable net-libs/gnome-online-accounts support

libgit2

gssapi	Enable GSSAPI support for SPNEGO auth
ssh	Enable SSH transport support
trace	Enable tracing support

libgit2-glib

ssh	Enable SSH transport support

libgpg-error

common-lisp	Install common-lisp files

libgpiod

tools	Build some useful gpio tools that use libgpiod.

libical

glib	Enable dev-libs/glib interface support

libisoburn

external-filters	Allow the use of external processes as file content filters (Note: this is a potential security risk)
external-filters-setuid	Also allow the use of external setuid processes as file content filters (Note: this is a potential security risk)
frontend-optional	Use dev-tcltk/bwidget which is not strictly required for the frontend
launch-frontend	Enable the tcl gui for xorriso
launch-frontend-setuid	Enable the tcl gui for xorriso under setuid

libisofs

verbose-debug	Enable verbose debug messages

libjcat

ed25519	Enable ED25519 verification support via dev-libs/nettle and net-libs/gnutls
gpg	Enable GPG verification support via app-crypt/gpgme
pkcs7	Enable PKCS7 verification support via net-libs/gnutls

libjwt

openssl	Use openssl libs for crypto functions

liblogging

rfc3195	Enables RFC 3195 protocol (aka syslog-reliable) support. If you don't know what this is, you don't need it!
stdlog	Enables liblogging's core component (think of it as a the next version of the syslog(3) API).

libmemcached

hsieh	Use Hsieh hash algorithm.
libevent	Use the libevent event loop interface.
sasl	Use sasl auth for communications.

libmemcached-awesome

libevent	Use the libevent event loop interface.
sasl	Use sasl auth for communications.

libnfc

pcsc-lite	Enable NFC drivers that require pcsc-lite

libnl

python	Install experimental dev-lang/python bindings
utils	Install command line interface utils

liborcus

spreadsheet-model	Enable the spreadsheet model implementation
tools	Build various low-level parsers

libowfat

diet	Compile against dev-libs/dietlibc

libp11

doc	Generate and install API documentation for the package.

libpcre

bzip2	Add support for pcregrep command to search within bzip2-compressed files (via app-arch/bzip2).
pcre16	Build PCRE library for 16 bit characters (e.g. UTF-16).
pcre32	Build PCRE library for 32 bit characters (e.g. UTF-32).
readline	Add support for command line editing to pcretest, through sys-libs/readline.
zlib	Add support for pcregrep command to search within gzip-compressed files (via sys-libs/zlib).

libpcre2

bzip2	Add support for pcregrep command to search within bzip2-compressed files (via app-arch/bzip2).
pcre16	Build PCRE library for 16 bit characters (e.g. UTF-16).
pcre32	Build PCRE library for 32 bit characters (e.g. UTF-32).
readline	Add support for command line editing to pcretest, through sys-libs/readline.
zlib	Add support for pcregrep command to search within gzip-compressed files (via sys-libs/zlib).

libpeas

glade	Install the glade catalog
javascript	Enable JavaScript support using dev-libs/gjs
python	Build support for loading dev-lang/python plugins

libpy

sparsehash	Include libpy wrappers for dev-cpp/sparsehash

librdkafka

lz4	Enable support for Kafka's LZ4 compression based on KIP-57 (uses app-arch/lz4)

librelp

gnutls	Use GnuTLS
openssl	Use OpenSSL

libsecp256k1

ecdh	Enable ECDH shared secret computation
ellswift	Enable ElligatorSwift encoding for public keys
endomorphism	Enable endomorphism
experimental	Allow experimental USE flags
extrakeys	Enable extrakeys module
lowmem	Reduce runtime memory usage at the expense of performance (ecmult window size 4, gen precision 2)
musig	Enable MuSig2 module
recovery	Enable ECDSA pubkey recovery module
schnorr	Enable Schnorr signature module
test-openssl	Enable OpenSSL comparison tests

libslz

tools	Install additional tools (zenc, zdec)

libsodium

urandom	Use /dev/urandom instead of /dev/random

libtermkey

demos	Install demos, which pulls in dev-libs/glib

libtomcrypt

libtommath	Uses dev-libs/libtommath for mathematical operations
tomsfastmath	Uses dev-libs/tomsfastmath for mathematical operations

libucl

regex	Enable regex support
sign	Enable signatures check
urls	Enable URLs fetch
utils	Install utils for checking other configs

libunibreak

doc	Install html API documentation.

libverto

glib	Support event loops using dev-libs/glib
libev	Support event loops using dev-libs/libev
libevent	Support event loops using dev-libs/libevent

libvoikko

expvfst	Enable experimental features of VFST morphology backend
hfst	Enable HFST morphology backend

libxlsxwriter

openssl	Use dev-libs/openssl for MD5 digest

libxmlb

stemmer	Enable language stemming support

libzia

ftdi	Enable support for FTDI USB chips

libzip

mbedtls	Use net-libs/mbedtls as TLS provider
tools	Install binary tools to compare, modify and merge zip files

link-grammar

aspell	Adds support for app-text/aspell spell checker
hunspell	Adds support for app-text/hunspell spell checker

log4cplus

explicit-initialization	Require explicit initialization
iconv	Use inconv for wchar_t <-> char conversions. See also log4cplus's unicode.txt documentation
server	Build the logging server

log4cxx

smtp	Offer SMTP support via net-libs/libesmtp

m17n-lib

X	Build the Graphical User Interface API and utilities
anthy	Enable support for app-i18n/anthy input method
athena	Enable the MIT Athena widget set (x11-libs/libXaw)
gd	Build API and utilities based on media-libs/gd. This flag is only meaningful if the X USE flag is also enabled
libotf	Use dev-libs/libotf to handle OpenType fonts
libxml2	Use dev-libs/libxml2 to parse XML

mimalloc

hardened	Enable exploit mitigations

modsecurity

fuzzyhash	Support fuzzy hash computations (to detect malware, for example) using the app-crypt/ssdeep package.
geoip2	Pull in dev-libs/libmaxminddb for use by the SecGeoLookupDb directive.
json	Suppose JSON in the request body parser through dev-libs/yajl.
lmdb	Add LMDB backend support
pcre2	Use dev-libs/libpcre2 as regex implementation

ncnn

tools	Enable installation of various tools in addition to the library

nss

cacert	Include root/class3 certs from CAcert (https://www.cacert.org/)
test-full	Run all available tests, instead of the standard set only
utils	Compile and install all extra binaries, such as certutil, modutil and few more

nwjs

ffmpeg-chromium	Use Chromium FFmpeg fork (media-video/ffmpeg-chromium) rather than mainline FFmpeg (media-video/ffmpeg)

oneDNN

cblas	Use virtual/cblas for sgemm routines
mkl	Use sci-libs/mkl for sgemm routines

onigmo

combination-explosion-check	enable combination explosion check
crnl-as-line-terminator	enable CR+NL as line terminator

oniguruma

crnl-as-line-terminator	Enable CR+NL as line terminator

opencryptoki

tpm	Enable support for Trusted Platform Module (TPM) using app-crypt/trousers

openct

debug	Add debug output to the driver library for pcsc-lite.
pcsc-lite	Build a driver library for sys-apps/pcsc-lite, providing PC/SC API access to devices supported by OpenCT.

openobex

irda	Enable IrDA support

opensc

ctapi	Use CT-API for accessing Smartcard hardware
notify	Enable notifications
openct	Use dev-libs/openct (and CT-API) for accessing Smartcard hardware
pace	Use dev-libs/openpace for EAC version 2 support
pcsc-lite	Use sys-apps/pcsc-lite (and PC/SC API) for accessing Smartcard hardware
secure-messaging	Enable secure messaging

openssl

bindist	Disable/Restrict EC algorithms (as they seem to be patented) -- note: changes the ABI
fips	Enable FIPS provider
ktls	Enable support for Kernel implementation of TLS (kTLS)
quic	Enable support for QUIC (RFC 9000); a UDP-based protocol intended to replace TCP
rfc3779	Enable support for RFC 3779 (X.509 Extensions for IP Addresses and AS Identifiers)
sslv2	Support for the old/insecure SSLv2 protocol -- note: not required for TLS/https
sslv3	Support for the old/insecure SSLv3 protocol -- note: not required for TLS/https
tls-compression	Enable support for discouraged TLS compression
tls-heartbeat	Enable the Heartbeat Extension in TLS and DTLS
weak-ssl-ciphers	Build support for SSL/TLS ciphers that are considered "weak"

openssl-compat

bindist	Disable/Restrict EC algorithms (as they seem to be patented) -- note: changes the ABI
rfc3779	Enable support for RFC 3779 (X.509 Extensions for IP Addresses and AS Identifiers)
sslv2	Support for the old/insecure SSLv2 protocol -- note: not required for TLS/https
sslv3	Support for the old/insecure SSLv3 protocol -- note: not required for TLS/https
tls-compression	Enable support for discouraged TLS compression
tls-heartbeat	Enable the Heartbeat Extension in TLS and DTLS
weak-ssl-ciphers	Build support for SSL/TLS ciphers that are considered "weak"

optix

headers-only	Download and install only the header files

pkcs11-helper

nss	Enable NSS crypto engine

pocl

accel	Enable the generic hardware accelerator device driver
conformance	Ensures that certain build options which would result in non-conformant pocl build stay disabled. Note that this does not quarantee a fully conformant build of pocl.
float-conversion	When enabled, OpenCL printf() call's f/e/g formatters are handled by pocl. When disabled, these are handled by system C library.
hardening	Enable hardening against various attacks. May worsen performance
hwloc	Enable hwloc support
memmanager	Enables custom memory manager. Except for special circumstances, this should be disabled

poco

7z	Add Support for the 7z archive format
activerecord	Add ActiveRecord support
cppparser	Build and install a minimal C++ parser
data	Database abstraction layer to easily send/retrieve data to/from various databases
file2pagecompiler	Utility to convert ordinary files to Page Compiler source files
json	Add JSON support
jwt	Add JSON Web Token support
mariadb	Prefer dev-db/mariadb-connector-c over dev-db/mysql-connector-c
mongodb	Add dev-db/mongodb support
net	Classes to write network clients & servers
pagecompiler	Simple compiler translating HTML pages containing embedded C++ code into HTTPRequestHandler classes
pocodoc	POCO documentation generator
prometheus	Add prometheus monitoring system support
ssl	Encryption and digital signing classes
util	Several utility classes (like logger, timer, config file parser)
zip	Add support for the zip & gz archive formats

ppl

cdd	Build the ppl_lcdd program for vertex/facet enumeration accepting the same input format as the programs shipped with sci-libs/cddlib and sci-libs/lrslib
lpsol	Build the ppl_lpsol linear program solver that uses sci-mathematics/glpk for its input routines

protobuf

conformance	Build conformance tests
libprotoc	Build libprotoc
libupb	Build libupb
protobuf	Build protobuf libraries and protoc compiler
protoc	Build libprotoc and protoc compiler

qcoro

network	Build dev-qt/qtbase network support
qml	Enable QML/QtQuick support via dev-qt/qtdeclarative
websockets	Build dev-qt/qtwebsockets support

qcoro5

network	Build dev-qt/qtnetwork support
qml	Enable QML/QtQuick support via dev-qt/qtdeclarative
testlib	Install coroutine-friendly versions of dev-qt/qttest macros
websockets	Build dev-qt/qtwebsockets support

qhotkey

qt6	Use Qt6 dependencies

quazip

qt5	Build with Qt5 support
qt6	Build with Qt6 support

raft

zfs	ZFS support

re2

benchmark	Build a benchmark binary, install it as re2-bench
test-full	Run additional, quite slow tests

rocksdb

numa	Enable NUMA support
tbb	Enable support for dev-cpp/tbb

sentry-native

breakpad	Use dev-util/breakpad as the crash handler
curl	Enable support for automated uploading of crash reports

serd

tools	Build command line utilities

serdisplib

tools	Build optional tools.

sexpp

cli	Build sexp console application

simdjson

all-impls	Enable all implementations rather than only onem
tools	Build and install extra command line tools

softhsm

gost	Enable gost algorithm
migration-tool	Build db migration tool

sord

tools	Build command line utilities

starpu

spinlock-check	Enable spinlock check

thrift

libevent	Build support for dev-libs/libevent

tinyxml

stl	Compile with TIXML_USE_STL support

tntnet

server	Enable tntnet server daemon

totem-pl-parser

archive	Enables ISO detection with app-arch/libarchive
crypt	Support AmazonAMZ decoding with dev-libs/libgcrypt
uchardet	Enable charset discovery via app-i18n/uchardet

tre

agrep	Build agrep tool
alloca	Enable if you want TRE to use alloca() instead of malloc() when allocating memory needed for regexec operations
approx	Enable the approximate matching functionality

uriparser

unicode	Add support for functions working with character type wchar_t (e.g. uriParseSingleUriW with trailing "W") which increases compile time and resulting binary file size by roughly factor 2.

weston

desktop	Enable the desktop shell
drm	Enable drm compositor support
editor	Install wayland-editor example application
fullscreen	Enable fullscreen shell
gles2	Enable the GLESv2 renderer, not just the x11-libs/pixman-based software fallback
headless	Headless backend and a noop renderer, mainly for testing purposes
ivi	Enable the IVI shell
kiosk	Enable the kiosk shell
pipewire	Enable virtual remote output with Pipewire on DRM backend
rdp	Enable Remote Desktop Protocol compositor support
remoting	Enable plugin to stream output to remote hosts using media-libs/gstreamer
resize-optimization	Increase performance, allocate more RAM. Recommended to disable on Raspberry Pi
screen-sharing	Enable screen-sharing through RDP
wayland-compositor	Enable Wayland compositor support
xwayland	Enable ability support native X11 applications

xerces-c

iconv	Use iconv (virtual/libiconv) as message loader and transcoder (in general it would be possible to use iconv only as message loader and something else like icu or the native method as transcoder and vice-versa, but this is a less common case and hard to handle)
threads	Enable threading support through pthread (or other libraries on AIX, IRIX, HPUX, Solars). Highly recommended

xmlrpc-c

abyss	Build the Abyss mini web-server.
libxml2	Use dev-libs/libxml2 to parse XML instead of the internal expat library.
threads	Controls whether to build the Abyss web-server with pthreads or fork 'threading'.

xmlsec

gcrypt	Install xmlsec-gcrypt library
gnutls	Install xmlsec-gnutls library
http	Allow fetching over HTTP via libxml2.
nss	Install xmlsec-nss library
openssl	Install xmlsec-openssl library

yaz

ziffy	Install ziffy, a promiscuous Z39.50 APDU sniffer

dev-lisp

clisp

hyperspec	Use local hyperspec instead of online version
svm	Build CLISP with support for the Support Vector Machine module

clx

doc	Builds documentation

cmucl

doc	Installs package documentation
gui	Build CLX, CLM, or Hemlock
source	Include source code for CMUCL in installation

ecl

gengc	Use generational garbage collection (experimental)
precisegc	Use type information during garbage collection (experimental)
unicode	Make the produced lisp support unicode

gcl

ansi	Build a GCL with ANSI support (else build a traditional CLtL1 image)
athena	Build xgcl - an interface to x11-libs/libXaw

sbcl

system-bootstrap	Bootstrap SBCL using either system SBCL installation or dev-lisp/clisp
unicode	Make the produced lisp support unicode

dev-lua

lua-cjson

internal-fpconv	Enable internal number conversion routines, can increase overall performance by up to 50%

dev-ml

lablgtk

sourceview	Enable GtkSourceView (x11-libs/gtksourceview) support

logs

cli	Enables the Logs_cli library that provides command line support for controlling Logs.
fmt	Enables the Logs_fmt reporter.
lwt	Enables the Logs_lwt library that provides Lwt logging functions.

ocaml-fileutils

ocamlopt	Whether the OCaml native code compiler is used. Must be set globally and match dev-lang/ocaml.

ocaml-gettext

ocamlopt	Whether the OCaml native code compiler is used. Must be set globally and match dev-lang/ocaml.

ocaml-gettext-camomile

ocamlopt	Whether the OCaml native code compiler is used. Must be set globally and match dev-lang/ocaml.

ocaml-gettext-stub

ocamlopt	Whether the OCaml native code compiler is used. Must be set globally and match dev-lang/ocaml.

ocamlnet

httpd	Enables net-httpd web server component
zip	Enables netzip support to read/write gzip data using object channels

stdlib-shims

ocamlopt	Whether the OCaml native code compiler is used. Must be set globally and match dev-lang/ocaml.

tiny_httpd

camlzip	Interface to camlzip for tiny_httpd

uutf

utftrip	Builds and install the utftrip executable: Among other things, reads unicode on stdin and rewrites it on stdout.

dev-perl

App-Nopaste

browser	Spawn browser with pasted page
clipboard	copying of URLs with -x/--copy
gitlab	Ensure git is installed for reading/passing GitLab authentication
pastebin	pastebin.com support

Boulder

genbank	Provide support with Boulder::Genbank for decoding Genbank data records
store	Provide support with Boulder::Store for persisting Stone objects

Business-ISBN

barcode	Install dev-perl/GD-Barcode for rendering ISBN numbers as barcodes

Config-Any

conf	Install dev-perl/Config-General to support decoding .conf/.cnf files
ini	Install dev-perl/Config-Tiny to support decoding INI config files
json	Install support libraries to support decoding JSON config files
xml	Install support libraries to support decoding XML config files
yaml	Install support libraries to support decoding YAML config files

Cookie-Baker

xs	Install dev-perl/Cookie-Baker-XS for accelerated performance

Coro

ev	Build support for using dev-perl/EV as an event-loop via Coro::EV
event	Build support for using dev-perl/Event as an event-loop via Coro::Event

DBD-MariaDB

mariadb	Use dev-db/mariadb-connector-c as the client library
mysql	Use dev-db/mysql-connector-c as the client library

DBD-SQLite

system-sqlite	Use the system-wide dev-db/sqlite installation

DBD-mysql

mariadb	Use dev-db/mariadb-connector-c as the client library
mysql	Use dev-db/mysql-connector-c as the client library
ssl	Compile in support for SSL connections via libmysqlclient

DBIx-Class

admin	Modules required for the DBIx::Class administrative library
admin-script	Modules required for the CLI DBIx::Class interface dbicadmin
deploy	Modules required for "deploy" in DBIx::Class::Storage::DBI and "deploymen_statements" in DBIx::Class::Storage::DBI
replicated	Modules required for DBIx::Class::Storage::DBI::Replicated

File-HomeDir

xdg	Ensure XDG Semantics for returned paths via x11-misc/xdg-user-dirs

File-Which

pwhich	Install dev-perl/App-pwhich which used to be a part of this package

GD

animgif	Enable animated gif support
fcgi	Build for FastCGI compatibility via dev-libs/fcgi instead of using PerlIO

HTML-Mason

modperl	Enable www-apache/mod_perl support

HTTP-Entity-Parser

xs	Install C-Based dependieces for faster performance

JSON

xs	Install C-based dev-perl/JSON-XS for faster performance

JSON-MaybeXS

xs	Install a C-Based backend to make JSON encode/decode fast

List-MoreUtils

xs	Install C-Based backend implementation for performance

MCE

sereal	Install dev-perl/Sereal-Encoder and decoder for faster worker IPC

Mail-IMAPClient

md5	Install support for DIGEST-MD5 and CRAM-MD5 Authentication
ntlm	Install support for NTLM Authentication
ssl	Install support for SSL Connections
zlib	Install support for COMPRESS DEFLATE connections

Net-SSH2

gcrypt	Use libgcrypt instead of openssl

PDL

badval	Enable bad values support
hdf	Enable HDF (version 4) format support
netpbm	Enable NETPBM and MPEG support
pdl2	Build pdf2 shell (requires Devel-REPL)
pgplot	Enable PGPLOT plotting capabilities

Ref-Util

xs	Install C-Based dev-perl/Ref-Util-XS for accelerated performance

Sub-Name

suggested	Install extra dependencies needed for extended regression tests

Sysadm-Install

hammer	Enable hammer() funtion to run a command in the shell and simulate a user hammering the ENTER key to accept defaults on prompts

Test-Warnings

suggested	Install optional dependencies for extra tests

Text-CSV

xs	Install dev-perl/Text-CSV_XS for accelerated decoding

WWW-Form-UrlEncoded

xs	Install C-Based dependieces for faster performance

perl-headers

debug	Add source locations in generated .ph files to assist with debugging when errors occur
sizeof-warning	Include logic to warn when a .ph file tries to use a sizeof() that is unknown

dev-php

maxmind-db-reader

extension	Build the C extension that uses dev-libs/libmaxminddb

pecl-apcu

lock-pthreadmutex	Enable pthread mutex locking
lock-pthreadrw	Enable pthread read/write locking
lock-semaphore	Enable semaphore locks instead of fcntl
lock-spinlock	Enable spin locks (EXPERIMENTAL)

pecl-event

extra	Add support of the Libevent extra API

pecl-memcached

igbinary	Enable support for the igbinary serializer
json	Enable support for json serialization

pecl-redis

igbinary	Enables igbinary serialisation support
json	Enables json serializer support

dev-python

PyQt5

bluetooth	Build bindings for the QtBluetooth module
dbus	Build bindings for the QtDBus module
declarative	Build bindings for the QtQml and QtQuick modules and enable the qmlscene plugin
designer	Build bindings for the QtDesigner module and enable the designer plugin
gui	Build bindings for the QtGui module
help	Build bindings for the QtHelp module
location	Build bindings for the QtLocation module
multimedia	Build bindings for the QtMultimedia module
network	Build bindings for the QtNetwork module
opengl	Build bindings for the QtOpenGL module
positioning	Build bindings for the QtPositioning module
printsupport	Build bindings for the QtPrintSupport module
sensors	Build bindings for the QtSensors module
serialport	Build bindings for the QtSerialPort module
speech	Build bindings for the QtTextToSpeech module
sql	Build bindings for the QtSql module
svg	Build bindings for the QtSvg module
testlib	Build bindings for the QtTest module
webchannel	Build bindings for the QtWebChannel module
websockets	Build bindings for the QtWebSockets module
widgets	Build bindings for the QtWidgets module
x11extras	Build bindings for the QtX11Extras module
xmlpatterns	Build bindings for the QtXmlPatterns module

PyQt6

bluetooth	Build bindings for the QtBluetooth module
dbus	Build bindings for the QtDBus module
designer	Build bindings for the QtDesigner module and enable the designer plugin
gui	Build bindings for the QtGui module
help	Build bindings for the QtHelp module
multimedia	Build bindings for the QtMultimedia module
network	Build bindings for the QtNetwork module
nfc	Build bindings for the QtNfc module
opengl	Build bindings for the QtOpenGL module
pdfium	Build bindings for the QtPdf module (uses pdfium from dev-qt/qtwebengine)
positioning	Build bindings for the QtPositioning module
printsupport	Build bindings for the QtPrintSupport module
qml	Build bindings for the QtQml module and enable the qml plugin
quick	Build bindings for the QtQuick module
quick3d	Build bindings for the QtQuick3D module
remoteobjects	Build bindings for the QtRemoteObjects module
sensors	Build bindings for the QtSensors module
serialport	Build bindings for the QtSerialPort module
spatialaudio	Build bindings for the QtSpatialAudio module
speech	Build bindings for the QtTextToSpeech module
sql	Build bindings for the QtSql module
svg	Build bindings for the QtSvg module
testlib	Build bindings for the QtTest module
webchannel	Build bindings for the QtWebChannel module
websockets	Build bindings for the QtWebSockets module
widgets	Build bindings for the QtWidgets module
xml	Build bindings for the QtXml module

PyQt6-WebEngine

quick	Build bindings for the QtWebEngineQuick module
widgets	Build bindings for the QtWebEngineWidgets module

QtPy

designer	Pull in bindings for the QtDesigner module and enable the designer plugin
gui	Pull in bindings for the QtGui module
help	Pull in bindings for the QtHelp module
multimedia	Pull in QtMultimedia and QtMultimediaWidgets modules
network	Pull in bindings for the QtNetwork module
opengl	Pull in bindings for the QtOpenGL module
positioning	Pull in bindings for the QtPositioning module
printsupport	Pull in bindings for the QtPrintSupport module
pyqt5	Use dev-python/PyQt5 as Qt for Python implementation
pyqt6	Use dev-python/PyQt6 as Qt for Python implementation
pyside2	Use dev-python/pyside2 as Qt for Python implementation
pyside6	Use dev-python/pyside6 as Qt for Python implementation
qml	Build bindings for the QtQml
quick	Build bindings for the QtQuick
sensors	Pull in bindings for the QtSensors module
serialport	Pull in bindings for the QtSerialPort module
speech	Pull in bindings for the QtTextToSpeech module
sql	Pull in bindings for the QtSql module
svg	Pull in bindings for the QtSvg module
testlib	Pull in bindings for the QtTest module
webchannel	Pull in bindings for the QtWebChannel module
webengine	Pull in QtWebEngine and QtWebEngineWidgets modules
websockets	Pull in bindings for the QtWebSockets module
widgets	Pull in bindings for the QtWidgets module
xml	Pull in QtXml module

amqp

extras	Install extra tools to generate initial Python mod from an AMQP XML file

apprise

dbus	Support sending notifications to the desktop over D-Bus
mqtt	Support sending notifications over MQTT

autobahn

xbr	Add support for XBR decentralized data markets and etherium blockchain

blake3

rust	Build the Rust implementation (if disabled, the "experimental" C implementation is used instead).

bpython

clipboard	Enable copying to clipboard using dev-python/pyperclip
jedi	Enable autocompletion using dev-python/jedi
watch	Enable watching paths using dev-python/watchdog

cbor2

native-extensions	Compiles native "C" extensions (speedups, instead of using python fallback code).

cvxopt

dsdp	Use interior point library sci-libs/dsdp
glpk	Use GNU Linear Programming Kit sci-mathematics/glpk

dnspython

dnssec	Use dev-python/cryptography to enable low-level DNSSEC RSA, DSA, ECDSA and EdDSA signature validation.

editorconfig

cli	Install command line interface as well as python library

fritzconnection

qrcode	Install dependencies needed to generate QR Codes for WiFi login.

frozenlist

native-extensions	Compile native C extensions (speedups, instead of using Python fallback code).

google-api-core

grpc	Pull (heavy) gRPC dependencies in, that are optionally required by part of the API.

httpx

cli	Install the CLI "httpx" client.

hypothesis

cli	Install a CLI tool used to write tests.

icalendar

doc	Generate examples and other extra documentation

immutables

native-extensions	Compiles native "C" extensions (speedups, instead of using Python fallback code).

ipython

nbconvert	Enable support for converting notebooks to various formats using app-text/pandoc
notebook	Install requirements for the web notebook based on dev-python/tornado

markdown-exec

ansi	Enable support for rendering ANSI colours in HTML code blocks

matplotlib

excel	Pull dev-python/xlwt for the exceltools toolkit
gtk3	Enable x11-libs/gtk+:3 support
webagg	Enable webagg backend that uses dev-python/tornado

mido

portmidi	Support using media-libs/portmidi as MIDI back-end
rtmidi	Support using media-libs/rtmidi as MIDI back-end

mkdocs-material

social	Install the dependencies of the "social" plugin.

msgpack

native-extensions	Compiles native "C" extensions (speedups, instead of using python fallback code).

multidict

native-extensions	Compile native C extensions (speedups, instead of using Python fallback code).

mypy

native-extensions	Compiles native C extensions (speedups, instead of using Python fallback code).

netcdf4

blosc	Allow using blosc compression via dev-libs/c-blosc

pandas

full-support	Pull all packages to give pandas full support

paramiko

server	Enable server feature

peewee

native-extensions	Compiles native C extension for more complete SQLite3 support.

pillow

imagequant	Build with Image Quantization Library support

pivy

quarter	Use media-libs/quarter for GUI bindings
soqt	Use media-libs/SoQt for GUI bindings

pyarrow

parquet	Enables read/write parquet data format

pyglet

image	Enable support for image formats other than PNG and BMP

pymongo

native-extensions	Compiles native C extensions
test-full	Run test suite in full, including tests that run a local database instance.

pyopengl-accelerate

numpy	Building NumPy native format handlers.

pypax

ptpax	Enable PT_PAX_FLAGS support.
xtpax	Enable XATTR_PAX_FLAGS support.

pypy

full-stdlib	Install complete stdlib as necessary to use PyPy for general purpose programs. By default, only a limited subset that is used when building PyPy3 executables is installed. Note that PyPy2.7's stdlib contains multiple known vulnerabilities.

pypy-exe

low-memory	Build using PyPy with the engine configured towards low memory footprint. This makes it possible to build PyPy using ~3.5G of RAM on amd64 and ~half of that on x86, at the cost of lengthened build time.

pypy3

test-install	Install the test suite packages, that are required to run tests in a few reverse dependencies.

pypy3_10

ensurepip	Install the ensurepip module that uses bundled wheels to bootstrap pip and setuptools (if disabled, it will be only possible to use venv `--without-pip`)
test-install	Install the test suite packages, that are required to run tests in a few reverse dependencies.

pypy3_10-exe

low-memory	Build using PyPy with the engine configured towards low memory footprint. This makes it possible to build PyPy using ~3.5G of RAM on amd64 and ~half of that on x86, at the cost of lengthened build time.

pyrsistent

native-extensions	Compiles native C extensions (speedups, instead of using python fallback code).

pyside2

3d	Build Qt3DCore, Qt3DAnimation, Qt3DExtras, Qt3DInput, Qt3DLogic, and Qt3DRender modules
charts	Build QtCharts module
concurrent	Build QtConcurrent module
datavis	Build QtDataVisualization module
designer	Build QtDesigner and QtUiTools modules
gles2-only	Build QtGui "QOpenGL*" classes
gui	Build QtGui module
help	Build QtHelp module
location	Build QtLocation module
multimedia	Build QtMultimedia and QtMultimediaWidgets modules
network	Build QtNetwork module
positioning	Build QtPositioning module
printsupport	Build QtPrintSupport module
qml	Build QtQml module
quick	Build QtQuick and QtQuickWidgets modules
scxml	Build QtScxml module
sensors	Build QtSensors module
speech	Build QtTextToSpeech module
sql	Build QtSql module
svg	Build QtSvg module
testlib	Build QtTest module
webchannel	Build QtWebChannel module
webengine	Build QtWebEngine and QtWebEngineWidgets modules
websockets	Build QtWebSockets module
widgets	Build QtWidgets module
x11extras	Build QtX11Extras module
xml	Build QtXml module
xmlpatterns	Build QtXmlPatterns module

pyside6

3d	Build Qt3DCore, Qt3DAnimation, Qt3DExtras, Qt3DInput, Qt3DLogic, and Qt3DRender modules
bluetooth	Build QtBluetooth module
charts	Build QtCharts module
concurrent	Build QtConcurrent module
designer	Build QtDesigner and QtUiTools modules
gles2-only	Build QtGui "QOpenGL*" classes
gui	Build QtGui module
help	Build QtHelp module
location	Build QtLocation module
multimedia	Build QtMultimedia and QtMultimediaWidgets modules
network	Build QtNetwork module
network-auth	Build QtNetworkAuth module
nfc	Build QtNfc module
pdfium	Build QtPdf module
positioning	Build QtPositioning module
printsupport	Build QtPrintSupport module
qml	Build QtQml module
quick	Build QtQuick and QtQuickWidgets modules
quick3d	Build QtQuick3D and QtQuickWidgets modules
scxml	Build QtScxml module
sensors	Build QtSensors module
serialport	Build QtSerialPort modules
spatialaudio	Build QtSpatialAudio module
speech	Build QtTextToSpeech module
sql	Build QtSql module
svg	Build QtSvg module
testlib	Build QtTest module
webchannel	Build QtWebChannel module
webengine	Build QtWebEngine and QtWebEngineWidgets modules
websockets	Build QtWebSockets module
widgets	Build QtWidgets module
xml	Build QtXml module

python-box

native-extensions	Compiles native C extensions

python-lsp-server

all-plugins	Pull in all optional plugins

python-mpd2

twisted	Enable twisted support

python-stdnum

vies	Enable VIES

pyudev

qt5	Install PyQt5 bindings

pyzmq

drafts	Enable draft API support

qiskit

visualization	Enable visualization modules

rarfile

compressed	Enables the module to support compressed v3 archives by calling the app-arch/unrar.

reedsolo

native-extensions	Compile native C extensions.

rfc3986

idna	enable support for the IDNA specification (RFC 5891)

rpyc

gdb	Run tests depending on dev-debug/gdb
numpy	Run tests depending on dev-python/numpy, dev-python/pandas

shiboken2

docstrings	Expose documentation as Python docstrings (recommended)
numpy	Implicitly convert passed NumPy arrays to Qt lists
vulkan	Generate "QSurface::VulkanSurface" bindings

shiboken6

docstrings	Expose documentation as Python docstrings (recommended)
numpy	Implicitly convert passed NumPy arrays to Qt lists
vulkan	Generate "QSurface::VulkanSurface" bindings

simplejson

native-extensions	Compiles native "C" extensions (speedups, instead of using Python fallback code).

stripe

telemetry	Enable sending "telemetry to Stripe regarding request latency and feature usage" by default. Upstream enables it by default in their PyPI distribution; it can also be explicitly controlled via stripe.enable_telemetry variable (boolean).

subprocess-tee

test-full	Enable full test mode. Pulls in many additional dependencies, and requires having been emerged without this flag first in order to avoid a circular dependency.

sympy

imaging	Add support for dev-python/pillow
ipython	Add support for dev-python/ipython
mathml	Add support for mathml
pyglet	Use dev-python/pyglet for plots and print preview
symengine	Add support for a dev-python/symengine backend
texmacs	Add app-office/texmacs interface

tables

cpudetection	Enables runtime CPU detection (useful for bindist, compatibility on other CPUs)

tpm2-pytss

fapi	Enable feature API (requires tpm2-tss be compile with thes same)

translate-toolkit

html	Support conversion between po and html files
ical	Support conversion between po and ical files
ini	Support conversion between po and ini files
subtitles	Support conversion between po and sub files
yaml	Support YAML format

twisted

conch	include Twisted SSHv2 implementation
serial	include serial port support

websockets

native-extensions	Compiles native C extensions

wrapt

native-extensions	Compiles native C extensions (speedups, instead of using python fallback code).

zeep

async	Add async support

dev-qt

designer

declarative	Build the qdeclarativeview plugin

linguist-tools

qml	Enable QML support in lupdate

qdoc

qml	Enable QML/JS parsing support

qt-creator

clang	Build clang-based plugins for C/C++ development (code model, formatting, static analysis)
designer	Enable designer for QtWidgets-based UIs
help	Enable the integrated dev-qt/qt-docs viewer (also needed for examples)
plugin-dev	Install the 'Devel' component needed to build external Qt Creator plugins
qmldesigner	Build QmlDesigner and related plugins (Insight, StudioWelcome)
serialterminal	Build the serial terminal plugin
tracing	Build plugins for tracing requiring extra dependencies (AppStatisticsMonitor, CtfVisualizer, PerfProfiler, QmlProfiler)
webengine	Use dev-qt/qtwebengine with the help USE rather than bundled litehtml

qt-docs

3d	Install documentation for dev-qt/qt3d
activeqt	Install documentation for ActiveQt (unpackaged, Windows-only)
assistant	Install documentation for dev-qt/assistant
bluetooth	Install documentation for dev-qt/qtbluetooth
charts	Install documentation for dev-qt/qtcharts
concurrent	Install documentation for dev-qt/qtconcurrent
connectivity	Install documentation for dev-qt/qtconnectivity
datavis	Install documentation for dev-qt/qtdatavis3d (unpackaged for Qt6)
declarative	Install documentation for dev-qt/qtdeclarative
designer	Install documentation for dev-qt/designer
gamepad	Install documentation for dev-qt/qtgamepad (available in qt overlay only)
graphicaleffects	Install documentation for dev-qt/qtgraphicaleffects
graphs	Install documentation for QtGraphs (unpackaged)
grpc	Install documentation for QtGRPC (unpackaged)
gui	Install documentation for dev-qt/qtgui
help	Install documentation for dev-qt/qthelp
html	Install documentation in HTML format
httpserver	Install documentation for QtHTTPServer (unpackaged)
imageformats	Install documentation for dev-qt/qtimageformats
linguist	Install documentation for dev-qt/linguist
location	Install documentation for dev-qt/qtlocation
lottie	Install documentation for QtLottie (unpackaged)
multimedia	Install documentation for dev-qt/qtmultimedia
network	Install documentation for dev-qt/qtnetwork
networkauth	Install documentation for dev-qt/qtnetworkauth
positioning	Install documentation for dev-qt/qtpositioning
printsupport	Install documentation for dev-qt/qtprintsupport
qch	Install documentation in QCH format
qdoc	Install documentation for dev-qt/qdoc
qt5compat	Install documentation for dev-qt/qt5compat
quick3d	Install documentation for dev-qt/qtquick3d
quick3dphysics	Install documentation for QtQuick3DPhysics (unpackaged)
quickcontrols	Install documentation for dev-qt/qtquickcontrols
quickcontrols2	Install documentation for dev-qt/qtquickcontrols2
quickeffectmaker	Install documentation for QtQuickEffectMaker (unpackaged)
remoteobjects	Install documentation for QtRemoteObjects (unpackaged)
script	Install documentation for dev-qt/qtscript
scxml	Install documentation for dev-qt/qtscxml
sensors	Install documentation for dev-qt/qtsensors
serialbus	Install documentation for dev-qt/qtserialbus (unpacakged for Qt6)
serialport	Install documentation for dev-qt/qtserialport
shadertools	Install documentation for dev-qt/qtshadertools
speech	Install documentation for dev-qt/qtspeech
sql	Install documentation for dev-qt/qtsql
svg	Install documentation for dev-qt/qtsvg
timeline	Install documentation for dev-qt/qtquicktimeline
tools	Install documentation for dev-qt/qttools
virtualkeyboard	Install documentation for dev-qt/qtvirtualkeyboard
wayland	Install documentation for dev-qt/qtwayland
webchannel	Install documentation for dev-qt/qtwebchannel
webengine	Install documentation for dev-qt/qtwebengine
websockets	Install documentation for dev-qt/qtwebsockets
webview	Install documentation for dev-qt/qtwebview (unpackaged for Qt6)
widgets	Install documentation for dev-qt/qtwidgets
x11extras	Install documentation for dev-qt/qtx11extras
xmlpatterns	Install documentation for dev-qt/qtxmlpatterns

qt3d

gamepad	Add support for gamepad hardware via dev-qt/qtgamepad
qml	Build QML/QtQuick bindings

qt5compat

qml	Build QML/QtQuick bindings and imports

qtbase

X	Build the XCB platform plugin and enable X11 integration
concurrent	Build Qt6Concurrent module
dbus	Build Qt6DBus module
eglfs	Build the EGL Full Screen/Single Surface platform plugin
evdev	Enable support for input devices via evdev
gssapi	Enable support for GSSAPI (virtual/krb5)
gtk	Build the GTK platform theme plugin
gui	Build Qt6Gui module
journald	Log messages using sys-apps/systemd's journald rather than output to stderr (override with the QT_FORCE_STDERR_LOGGING=1 env var)
libinput	Enable support for input devices via dev-libs/libinput
libproxy	Use net-libs/libproxy for automatic HTTP/SOCKS proxy configuration
network	Build Qt6Network module
renderdoc	Enable support for capturing graphic's API calls using media-gfx/renderdoc
sql	Build Qt6Sql module
syslog	Log messages using syslog rather than output to stderr (override with the QT_FORCE_STDERR_LOGGING=1 env var)
tslib	Enable support for touchscreen devices via x11-libs/tslib
widgets	Build Qt6Widgets module

qtbluetooth

qml	Build QML/QtQuick bindings and imports

qtcharts

qml	Build QML/QtQuick bindings and imports

qtconnectivity

neard	Use net-wireless/neard to access NFC devices
nfc	Enable support for the Near Field Communication protocol

qtcore

old-kernel	Disable syscalls not available on Linux kernels older than 4.11

qtdatavis3d

qml	Build QML/QtQuick bindings and imports

qtdeclarative

localstorage	Build the LocalStorage import for QtQuick (requires QtSql)
network	Enable QtNetwork support
opengl	Enable OpenGL support
qmlls	Build the qmlls tool using dev-qt/qtlanguageserver
sql	Enable QtSQL support
widgets	Enable QtWidgets support

qtdiag

network	Report network information
widgets	Report widget style information

qtgamepad

evdev	Enable support for input devices via evdev
qml	Build QML bindings

qtgui

X	Build the XCB platform plugin and enable X11 integration
eglfs	Build the EGL Full Screen/Single Surface platform plugin
evdev	Enable support for input devices via evdev
ibus	Build the IBus input method plugin
libinput	Enable support for input devices via dev-libs/libinput
linuxfb	Enable Linux framebuffer support for embedded devices
tslib	Enable support for touchscreen devices via x11-libs/tslib
tuio	Build plugin to receive touch events over the TUIO protocol
wayland	Provide dev-qt/qtwayland to ensure Qt applications can be run as Wayland clients

qthttpserver

websockets	Enable websockets support using dev-qt/qtwebsockets

qtmultimedia

eglfs	Enable screen capture support with Qt's EGL Full Screen/Single Surface platform plugin
gstreamer	Enable audio support via media-libs/gstreamer
qml	Build QML/QtQuick bindings and imports
widgets	Build the QtMultimediaWidgets module

qtnetwork

gssapi	Enable support for GSSAPI (virtual/krb5)
libproxy	Use net-libs/libproxy for automatic HTTP/SOCKS proxy configuration

qtpositioning

geoclue	Use enhanced location information from app-misc/geoclue
nmea	Build plugin for parsing NMEA (National Marine Electronics Association) sentences
qml	Build QML bindings

qtquickcontrols

widgets	Enable QtWidgets support

qtquickcontrols2

widgets	Enable QtWidgets support

qtremoteobjects

qml	Build QML/QtQuick bindings and imports

qtscript

scripttools	Build the QtScriptTools module (requires QtWidgets)

qtscxml

qml	Build QML/QtQuick bindings and imports

qtsensors

qml	Build QML bindings

qtspeech

flite	Enable text-to-speech synthesizer plugin using app-accessibility/flite engine
qml	Build QML/QtQuick bindings and imports
speechd	Enable text-to-speech synthesizer plugin using app-accessibility/speech-dispatcher engine

qttools

assistant	Build Qt Assistant and the QtHelp module
clang	Enable using libclang for code parsing (linguist/qdoc)
designer	Build Qt Designer
distancefieldgenerator	Build Qt Distance Field Generator
linguist	Build Qt Linguist (GUI requires USE=widgets)
pixeltool	Build Qt Pixeltool
qdbus	Build the Qt D-Bus Interface (D-Bus Viewer requires USE=widgets)
qdoc	Build Qt Documentation Generator
qml	Build QML/QtQuick bindings and imports
qmlls	Build the QtHelp plugin for the QML language server
qtattributionsscanner	Build Qt Source Code Attribution Scanner
qtdiag	Build Qt Diag
qtplugininfo	Build Qt Plugin Info
widgets	Enable QtWidgets support

qtvirtualkeyboard

handwriting	Adds handwriting recognition integration support

qtwayland

compositor	Enable support for the wayland compositor / server APIs
gnome	Build the GNOME-like decoration plugin (loaded by default with GNOME)
qml	Build QML/QtQuick bindings and imports
vulkan	Enable support for Vulkan-based server buffer integration

qtwebchannel

qml	Build QML/QtQuick bindings and imports

qtwebengine

designer	Install the QWebEngineView plugin used to add widgets in dev-qt/designer forms that display web pages.
jumbo-build	Combine source files to speed up build process.
pdfium	Build the QtPdf module based on chromium's PDFium library
qml	Build QML/QtQuick bindings and imports
system-icu	Use the system-wide dev-libs/icu instead of bundled.
webdriver	Build tool for automated testing (ChromeDriver equivalent)
widgets	Enable QtWidgets support

qtwebsockets

qml	Build QML bindings

qtwidgets

gtk	Build the GTK platform theme plugin

qtxmlpatterns

qml	Build the XmlListModel import for QtQuick (requires QtDeclarative)

dev-ruby

activesupport

msgpack	Support ActiveSupport::MessagePack module

asciidoctor-diagram

barcode	Enable diagrams with dev-ruby/rqrcode and dev-ruby/barby
ditaa	Enable diagrams with media-gfx/ditaa
lilypond	Enable diagrams with media-sound/lilypond
meme	Enable diagrams with media-gfx/imagemagick
mscgen	Enable diagrams with media-gfx/mscgen
plantuml	Enable diagrams with media-gfx/plantuml
tikz	Enable diagrams with dev-tex/pgf

barby

cairo	Add support for writing images (PNG, PS, EPS and, if supported, PDF and SVG) using dev-ruby/rcairo. Not available on JRuby.
png	Add support for writing PNG images using dev-ruby/chunky_png.
prawn	Add support for writing PDF documents using dev-ruby/prawn.
qrcode	Add support for QRCode 2D codes using dev-ruby/rqrcode.
rmagick	Add support for writing images (among others PNG, GIF and JPEG) using dev-ruby/rmagick. Not available on JRuby.

faraday_middleware

mashify	Include FaradayMiddleware::Mashify
oauth	Include FaradayMiddleware::OAuth
parsexml	Include FaradayMiddleware::ParseXml
rashify	Include FaradayMiddleware::Rashify

io-event

io-uring	Enable io_uring support, and use io_uring instead of epoll

jwt

eddsa	Support EdDSA algorithm using dev-ruby/rbnacl

maruku

highlight	Enable source code highlighting via dev-ruby/syntax

mysql2

mariadb	Use mariadb bindings

net-ssh

chacha20	Use dev-ruby/rbnacl for chacha20-poly1305@openssh.com support
ed25519	Use dev-ruby/ed25519 for Ed25519 support

rrdtool-bindings

graph	Enable support for graphing functions

rspec-core

highlight	Enable source code highlighting via dev-ruby/coderay

rubygems

server	Install support for the rubygems server

vcr

json	Add support for casettes serialized with JSON

dev-scheme

bigloo

avahi	Enable Avahi support
gpg	Enable GPG support
libuv	Enable libuv support

gauche-gl

cg	Enable NVidia Cg binding

guile

debug-freelist	Include garbage collector freelist debugging code
debug-malloc	Include malloc debugging code
deprecated	Enable deprecated features
discouraged	(implied by deprecated) enable merely discouraged features
networking	Include networking interfaces
regex	Include regular expression interfaces

kawa

awt	Assume AWT is available
frontend	Build "kawa" front-end program using sys-libs/readline
jemacs	Build JEmacs
krl	Build BRL emulation and KRL
sax	Assume SAX2 is available with dev-java/sax
servlets	Build support for generating servlets with Java servletapi
swing	Assume Swing is available

mit-scheme

blowfish	Compile with blowfish encryption support

racket

chez	Build Racket on Chez (Racket CS)
futures	Enable racket/future library for fine-grained hardware parallelism
ncurses	Add ncurses support for expeditor (REPL expression editor)
places	Enable racket/place library for share-nothing parallelism and message-passing communication. Compared to futures, places are heavyweight, but they have a simpler performance model.
threads	Enable support for green threads

scm

arrays	Support for arrays, uniform-arrays and uniform-vectors.
bignums	Support for large precision integers.
cautious	SCM will always check the number of arguments to interpreted closures.
dynamic-linking	Be able to load compiled files while running.
engineering-notation	Floats to display in engineering notation (exponents always multiples of 3) instead of scientific notation.
gsubr	generalized c arguments: for arbitrary (more then 11) arguments to C functions.
inexact	Support for floating point numbers.
ioext	Commonly available I/O extensions: line I/O, file positioning, file delete and rename, and directory functions.
libscm	Build and install libscm.a and related headers
macro	C level support for hygienic and referentially transparent macros (syntax-rules macros).
regex	String regular expression matching.
unix	Support for: nice, acct, lstat, readlink, symlink, mknod and sync.

slib

gambit	Support for gambit scheme implementation
scm	Support for scm scheme implementation

dev-tcltk

expect-lite

debug	pull in packages needed for runtime interactive debugger

tcl3d

ode	Enable support for physics engine from dev-games/ode
osg	Enable support for 3D toolkit from dev-games/openscenegraph

tktreectrl

shellicon	shellicon extension

dev-tex

abntex

lyx	Install with app-office/lyx layout

biblatex

biber	Install the unicode compatible backend processor

pythontex

highlighting	Syntax highlighting using dev-python/pygments

dev-texlive

texlive-basic

luajittex	Add support for LuaJitTeX: LuaTeX based on LuaJIT which is usually faster.

dev-util

Tensile

client	Build and install tensile_client executable to run benchmarks and tune GPU GEMM

babeltrace

elfutils	Build the dev-util/lttng-ust debug information filter component class
plugins	Build support for Babeltrace 2 Python plugins

bpftool

caps	Use sys-libs/libcap to enable unprivileged run support
clang	Use sys-devel/clang instead of sys-devel/bpf-toolchain for BPF CO-RE support
llvm	Use sys-devel/llvm instead of libbfd (sys-libs/binutils-libs) for JIT disassembly

breakpad

tools	Build tools

bugbite-cli

openssl	Use dev-libs/openssl as a crypto backend

buildbot

docker	Add support for worker docker command steps
irc	Add support for status delivery through an ircbot.

cargo-audit

fix	Add support for 'fix' subcommand (experimental)

catalyst

iso	Pulls in the depends for building iso images
qcow2	Pulls in the depends for building qcow2 images

ccache

redis	Enable Redis backend for storage via dev-libs/hiredis
static-c++	Avoid dynamic dependency on gcc's libstdc++.

cccc

apidoc	Build software docs with doxygen/graphviz and metrics with cccc
mfc	Add patch for MFC dialect options

codeblocks

contrib	Build additional contrib components
fortran	Build FortranProject plugin which enables to use Code::Blocks IDE for Fortran language

cppcheck

charts	Enable QtCharts usage in the GUI
htmlreport	install cppcheck-htmlreport

ctags

json	Enable JSON output support
xml	Enable XML parsing support
yaml	Enable YAML parsing support

cwdiff

mercurial	install hg wdiff alias for dev-vcs/mercurial

devhelp

gedit	Install plugin for app-editors/gedit

dialog

minimal	Disable library, install command-line program only

diffoscope

R	Use dev-lang/R
binutils	Use sys-devel/binutils
cpio	Use app-alternatives/cpio
diff	Use sys-apps/diffutils
docx	Use app-text/docx2txt
dtc	Use sys-apps/dtc
e2fsprogs	Use sys-fs/e2fsprogs
file	Use sys-apps/file
find	Use sys-apps/findutils
gettext	Use sys-devel/gettext
gpg	Use app-crypt/gnupg
haskell	Use dev-lang/ghc
hdf5	Use sci-libs/hdf5
hex	Use app-editors/vim-core
iso	Use app-cdr/cdrtools
llvm	Use sys-devel/llvm
opendocument	Use app-text/odt2txt
pascal	Use dev-lang/fpc
rpm	Use app-arch/rpm
squashfs	Use sys-fs/squashfs-tools
ssh	Use net-misc/openssh
tar	Use app-arch/tar
tcpdump	Use net-analyzer/tcpdump
zip	Use app-arch/unzip

dropwatch

bfd	Add support for Binary File Descriptor

edi

clang	Provide integration with sys-devel/clang and dev-util/bear for autocompletion, inline errors and information about compilation units.

flatpak-builder

yaml	Use libyaml for yaml support

geany

vte	Enable Terminal support (x11-libs/vte)

geany-plugins

ctags	Enable ctags plugin
debugger	Enable the debugger plugin which interfaces with dev-debug/gdb
enchant	Enable spell checking using enchant
gpg	Enable geanypg plugin which integrates GPG using app-crypt/gpgme
gtkspell	Use gtkspell for dictionary support in GeanyVC
markdown	Enable the markdown plugin
pretty-printer	Enable pretty-printer plugin
scope	Enable the scope plugin which is a graphical GDB front-end
webhelper	Enable webhelper plugin
workbench	Enable workbench plugin

glade

gjs	Build catalog support for dev-libs/gjs widgets.
webkit	Build catalog support for net-libs/webkit-gtk:4 widgets.

global

vim	Integrate the GNU GLOBAL source code tag system with Vim

gnome-builder

clang	Provide integration with sys-devel/clang for best possible C/C++ autocompletion, semantic highlighting, symbol resolving, and diagnostics support
d-spy	Provide D-Bus debugging functionality via dev-debug/d-spy
flatpak	Enable support for flatpak applications using sys-apps/flatpak
git	Provide support for the Git version control system via dev-libs/libgit2-glib (such as setup of Git for New Project, direct cloning for Open Project and changed lines indicators in the editor gutter)
sysprof	Provide an integrated profiler via dev-util/sysprof

google-perftools

debug	Build a set of libraries with debug support (so-called debugalloc). These are available by default but are not needed unless you're actually developing using tcmalloc.
minimal	Only build the tcmalloc_minimal library, ignoring the heap checker and the profilers.
optimisememory	To build libtcmalloc with smaller internal caches.
pagesize-128k	Use 128K page size for tcmalloc. Larger size makes tcmalloc faster, at the cost of using more space (due to internal fragmentation)
pagesize-16k	Use 16K page size for tcmalloc. Larger size makes tcmalloc faster, at the cost of using more space (due to internal fragmentation)
pagesize-256k	Use 256K page size for tcmalloc. Larger size makes tcmalloc faster, at the cost of using more space (due to internal fragmentation)
pagesize-32k	Use 32K page size for tcmalloc. Larger size makes tcmalloc faster, at the cost of using more space (due to internal fragmentation)
pagesize-64k	Use 64K page size for tcmalloc. Larger size makes tcmalloc faster, at the cost of using more space (due to internal fragmentation)

heaptrack

gui	Install Qt5-based analyzer tool

hfstospell

clang	Use different logic in ebuild when clang is used

hip

hip	Build HIP runtime
opencl	Build OpenCL runtime
video_cards_amdgpu	Build for AMD platform
video_cards_nvidia	Build for Nvidia platform

intel-graphics-compiler

vc	Enable VectorCompiler for a better performance.

intel-graphics-system-controller

cli	Build CLI tools for flashing manually a firmware upgrade.

kcov

binutils	Use sys-libs/binutils-libs for `--verify` support

kdevelop

gdbui	Enable GUI for attaching GDB to a running process
qmake	Enable support for QMake build system
share	Enable support for patch sharing using kde-frameworks/purpose

kernelshark

custom-optimization	Build with user-specified compiler optimizations (-Os, -O0, -O1, -O2, -O3) from CFLAGS

kup

gitolite	Enable support for dev-vcs/gitolite in kup-server

libabigail

btf	Handle reading kernel debug files in BTF format via dev-libs/libbpf

librnp

botan	Use Botan crypto backend instead of OpenSSL

lttng-tools

ust	Support LTTng-UST (Userspace Tracing)

lttng-ust

numa	Enable numa support

massif-visualizer

callgraph	Enable detailed snapshot analysis using media-gfx/kgraphviewer

mingw64-runtime

default-ucrt	Use ucrt instead of msvcrt-os as the default crt (WARNING: incompatible with each others and also for building Wine with USE=mingw, pick one from the start and keep it)
idl	Install idl files
libraries	Build extra libraries: mangle, pseh, winpthreads
tools	Build extra tools: gendef, genidl, widl

mingw64-toolchain

bin-symlinks	Symlink executables to usr/bin to be in default PATH (conflicts with crossdev mingw, and crossdev is preferable for a fully featured toolchain)

nvidia-cuda-toolkit

debugger	Install the CUDA debugger
nsight	Install profiling and optimizing tools (nsight-compute, nsight-systems)
profiler	Install the NVIDIA CUDA profiler (nvprof) and the related libraries
rdma	Enable infiniband support via sys-cluster/rdma-core
sanitizer	Install compute-sanitizer tool
vis-profiler	Install the NVIDIA CUDA visual profiler (nvvp)

oprofile

apidoc	Provide doxygen generated API docs.

ostree

archive	Use libarchive
dracut	Install dracut module
gpg	Enable GPG support
grub	Enable grub configuration generator
httpd	Enable ostree trivial-httpd entrypoint
libmount	Use libmount
sodium	Use libsodium for ed25519
soup	Use libsoup for networking

perf

babeltrace	Enable dev-util/babeltrace support
bpf	Enable support for eBPF features with dev-libs/libbpf
capstone	Use dev-libs/capstone for disassembly support
doc	Build documentation and man pages. With this USE flag disabled, the --help parameter for perf and its sub-tools will not be available. This is optional because it depends on a few documentation handling tools that are not always welcome on user systems.
libpfm	Enable dev-libs/libpfm support
libtraceevent	Enable dev-libs/libtraceevent support
libtracefs	Enable dev-libs/libtracefs support
numa	Enable NUMA support
perl	Add support for Perl as a scripting language for perf tools.
systemtap	Add support to define SDT event in perf tools.
unwind	Use sys-libs/libunwind for frame unwinding support.

pkgconf

native-symlinks	Install generic symlinks like pkgconf and pkg-config. If this flag is disabled, only CHOST-prefixed pkg-config executables will be available to end users and ebuilds.

plan9port

freefonts	Don't install BigelowHolmes fonts

poke

nbd	Enable poking at networked block devices via sys-libs/libnbd.
pvm-profiling	Enable profiling in the PVM

pycharm-community

bundled-jdk	Use bundled jdk

pycharm-professional

bundled-jdk	Use bundled jdk

ropper

z3	Enable Z3 contraint solver support

scanmem

gui	Enable the GameConqueror GUI

sccache

azure	Enable Azure Blob Storage support
dist-client	Enables distributed support in the sccache client
dist-server	Enables the sccache-dist binary
gcs	Enable Google Cloud Storage support
redis	Enable Redis support
s3	Enable full Amazon S3 support
simple-s3	Enable minimal Amazon S3 support

schroot

btrfs	Enable support for chroots using btrfs snapshots
dchroot	Enables the building of a wrapper named "dchroot", replacing sys-apps/dchroot
lvm	Enable support for chroots using LVM snapshots
zfs	Enable support for chroots using ZFS shapshots/clones

sdl-jstest

sdl	Enable media-libs/libsdl2 based input test
sdl1	Enable media-libs/libsdl based input test

selenium-manager

telemetry	Disable sending telemetry by default (avoid-stats config option).

sysprof

unwind	Use sys-libs/libunwind to unwind the stack

uftrace

capstone	Use capstone to provide dynamic tracing without recompilation

vulkan-tools

cube	Build the cube/cubepp demos

watchman

python	Install pywatchman bindings and the watchman-{wait,make} utils

dev-vcs

cvs

server	Enable server support

darcs

curl	Use libcurl for HTTP support.
terminfo	Use the terminfo package for enhanced console support.
threaded	Use threading and SMP support.

fossil

fusefs	Enable the Fuse Filesystem
json	Enable the JSON API of Fossil's wiki
system-sqlite	Use the system SQLite instead of the bundled one
tcl-private-stubs	Enable Tcl integration via private stubs mechanism
tcl-stubs	Enable Tcl integration via stubs library mechanism
th1-docs	Enable TH1 for embedded documentation pages
th1-hooks	Enable TH1 hooks for commands and web pages

git

blksha1	Use the new optimized SHA1 implementation
cgi	Install gitweb too
curl	Support fetching and pushing (requires webdav too) over http:// and https:// protocols
gpg	Pull in gnupg for signing -- without gnupg, attempts at signing will fail at runtime!
highlight	GitWeb support for app-text/highlight
mediawiki	Support pulling and pushing from MediaWiki
perforce	Add support for Perforce version control system (requires manual installation of Perforce client)
safe-directory	Respect the safe.directory setting
subversion	Include git-svn for dev-vcs/subversion support
tk	Include the 'gitk' and 'git gui' tools
webdav	Adds support for push'ing to HTTP/HTTPS repositories via DAV

git-annex

assistant	Enable git-annex assistant and watch command
benchmark	Enable benchmarking
dbus	Enable dbus support
gitlfs	Build with git-lfs library (rather than vendored copy)
magicmime	Use libmagic to determine file MIME types
pairing	Enable pairing
torrentparser	Use haskell torrent library to parse torrent files
webapp	Enable git-annex webapp

git-delete-merged-branches

full-name-executable	Install executable /usr/bin/git-delete-merged-branches that is in conflict with dev-vcs/git-extras

gitg

glade	Install a glade catalog file
python	Install Python bindings for those plugins requiring it.

gitolite

tools	Install tools to e.g. convert a Gitosis config to gitolite or one to check if your setup is gitolite >= 3.x compatible

gitolite-gentoo

tools	Install tools to e.g. convert a Gitosis config to gitolite or one to check if your setup is gitolite >= 3.x compatible

mercurial

chg	Support Mercurial command server client
gpg	Support signing with GnuPG.
rust	Use Rust extensions.
tk	Install dev-lang/tk for hgk script.

subversion

extras	Install extra scripts (examples, tools, hooks)
kwallet	Enable encrypted storage of passwords with kde-frameworks/kwallet
plaintext-password-storage	Enable on-disk caching of plaintext passwords and passphrases. (Enabling this functionality will not force Subversion to store passwords in plaintext, but does permit users to explicitly allow that behavior via runtime configuration.)

games-action

beathazardultra

bundled-libs	Use the upstream provided bundled libraries.

descent1-freedata

l10n_de	Provides German translations for the game's briefings, robot descriptions, and outro of the original campaign
opl3-musicpack	Include alternate version of the game's music, recorded with the Yamaha YMF262 OPL3 soundchip
sc55-musicpack	Include alternate version of the game's music, recorded with the Roland Sound Canvas SC-55 MIDI module
textures	Include high resolution (640x480) backgrounds, briefing images and fonts (Descent 1)

descent2-freedata

l10n_de	Provides German translations for the game's briefings, robot descriptions, and outro of the original campaign
opl3-musicpack	Include alternate version of the game's music, recorded with the Yamaha YMF262 OPL3 soundchip
sc55-musicpack	Include alternate version of the game's music, recorded with the Roland Sound Canvas SC-55 MIDI module

dxx-rebirth

d1x	Install Descent 1 resources and executable
d2x	Install Descent 2 resources and executable
data	Ensure some game levels are present; if the full game's level data is not already installed then install the playable demo data (i.e. shareware levels)
debug	Enable various debugging code paths and sanity checks, not just output. Some of these checks date back to the retail build, and choke on some custom levels because the game was never coded to sufficiently distrust inputs
editor	Enable level editor support
l10n_de	Provides German translations for the game's briefings, robot descriptions, and outro of the original campaign
midi	Enforce that SDL-mixer is used and has midi support
music	Enable music support
opl3-musicpack	Include alternate version of the game's music, recorded with the Yamaha YMF262 OPL3 soundchip
sc55-musicpack	Include alternate version of the game's music, recorded with the Roland Sound Canvas SC-55 MIDI module
sdl2	Use libSDL2, SDL2-mixer instead of libSDL-1* and SDL-mixer-1*
tracker	Enable support for the PHP-based multiplayer game tracker

hotline-miami

bundled-libs	Use bundled libraries.
launcher	Install qt launcher

prismlauncher

qt6	Build with Qt6 support instead of the default Qt5

supermariowar

server	Compile and install Super Mario War server files

supertuxkart

nettle	Use dev-libs/nettle crypto backend
recorder	Enable recording with media-libs/libopenglrecorder
sqlite	Record IP bans, statistics in server mode with dev-db/sqlite
wiimote	Support for wiimote input devices

swordandsworcery

bundled-libs	Use the upstream provided bundled libraries.

trine

launcher	Install GTK+ launcher

trine-enchanted-edition

launcher	Install GTK+ launcher

trine2

launcher	Install GTK+ launcher

games-arcade

bomns

editor	enables building the level editor

commandergenius

downloader	Allows some Keen games to be downloaded from the menu

jazz2

sdl	Prefer SDL2 over GLFW backend
server	Build the multiplayer game server

jazz2-data

cc	Install The Christmas Chronicles additional data
demo	Use the free demo data instead of the full retail game data

lbreakout2

themes	Install additional themes

moleinvasion

music	Download and install the music files

oshu

osu-skin	Include more complete osu-skin (other is minimal)

osu-lazer

pipewire	Use pipewire to enable sound output

performous

midi	Enable MIDI I/O support
songs	Install a few demo songs
webcam	Enable Webcam support

tuxanci

physfs	Use dev-games/physfs instead of dev-libs/libzip to load compressed data

games-board

cockatrice

client	Build with client
oracle	Build with oracle
server	Compile server support

crafty

no-opts	Don't try to enable crazy CFLAG options

freedoko

backgrounds	Install additional background images
gnomecards	Install the gnome-games card set
kdecards	Install the KDE card set
openclipartcards	Install the openclipartcards card set
pysolcards	Install the PySol card set
xskatcards	Install the XSkat card set

pasang-emas

extras	Install some extra themes

pioneers

help	Enable gnome ingame help via scrollkeeper

pysolfc

extra-cardsets	Install extra cardsets
sound	Enable sound support using dev-python/pygame

scid

photos	Install collection of player photos (large)
scripts	Install additional python and tcl utility scripts

stockfish

general-32	Generic unoptimized 32-bits build
general-64	Generic unoptimized 64-bits build
optimize	Enable upstream -O3 optimizations (default enabled)

tablebase-syzygy

6-pieces	Install tablebases for 6 pieces (huge!)

xboard

default-font	Install the default font that xboard uses
zippy	Enable experimental zippy client

games-emulation

atari800

encode-mp3	Support recording sound in MP3 format

bsnes-jg

jgmodule	Build module for The Jolly Good API
shared	Build shared library

desmume

gdb	Enable support for the remote GDB stub
openal	Use media-libs/openal for microphone input
wifi	Enable support for Wi-Fi (experimental and discouraged)

dolphin

discord-presence	Enables Discord Rich Presence, show the current game on Discord
evdev	Enable evdev input support
llvm	Enables LLVM support, for disassembly
log	Increase logging output
mgba	Enables GBA controllers emulation using libmgba.

dosbox

core-inline	Enable memory-increasing inlines for better performance but requiring more build time
glide	Enable unofficial Glide emulation via media-libs/openglide

dosbox-staging

dynrec	Use recompiling cpu core instead of dynamic x86/x64 specific cpu core
fluidsynth	use media-sound/fluidsynth for MIDI emulation
mt-32	use media-libs/munt-mt32emu for MT-32 emulation
network	Enable networking features (modem, ipx)
screenshot	Enable screenshots of rendered output using media-libs/sdl2-image
slirp	Enable Ethernet emulation using net-libs/libslirp

fceux

archive	Use app-arch/libarchive for 7zip support
ffmpeg	Use media-video/ffmpeg for video recording
x265	Use media-libs/x265 for video recording (HEVC)

gambatte-jg

jgmodule	Build module for The Jolly Good API
shared	Build shared library

generator

sdlaudio	Enable SDL Audio

hatari

capsimage	Use dev-libs/spsdeclib to read .IPF, .RAW, and .CTR disk images
capstone	Use dev-libs/capstone for disassembly output in the debugger
portmidi	Use media-libs/portmidi as an alternative MIDI backend

higan

gtk	Use GTK3 (Qt5 if disabled) user interface backend

jgemu

bsnes	Install bsnes for Super Nintendo
cega	Install Cega for SG-1000, Sega Master System and Game Gear
gambatte	Install Gambatte for Game Boy and Game Boy Color
geolith	Install Geolith for Neo Geo AES/MVS
jollycv	Install JollyCV for ColecoVision
mednafen	Install Mednafen for Atari Lynx, Nintendo Virtual Boy, NEC PC Engine, NEC SuperGrafx, Sony PlayStation, Sega Saturn, Super Nintendo, Neo Geo Pocket and WonderSwan
melonds	Install MelonDS for Nintendo DS
mgba	Install mGBA for Game Boy Advance
nestopia	Install Nestopia for Nintendo Entertainment System
prosystem	Install ProSystem for Atari 7800
sameboy	Install SameBoy for Game Boy and Game Boy Color
vecx	Install Vecx for Vectrex

m64py

7z	Ensure support for .7z archives.
rar	Ensure support for .rar archives.

mgba

discord	Enable Discord RPC support
elf	Enable the use of elf utils via dev-libs/elfutils
gles3	Build OpenGL ES 3.x RenderSystem
libretro	Build libretro port

mupen64plus

audio-sdl	Enable SDL audio plugin.
input-sdl	Enable SDL input plugin.
rsp-hle	Enable HLE RSP plugin.
ui-console	Enable default console UI.
ui-m64py	Enable PyQt5 UI using games-emulation/m64py.
video-glide64mk2	Enable Glide64mk2 video plugin.
video-rice	Enable Rice video plugin.

mupen64plus-core

debugger	Build the debugger
netplay	Enable netplay functionality
new-dynarec	Enable new experimental dynamic recompiler implementation (only for x86 and arm)
opencv	Support video capture via media-libs/opencv
osd	Overlay emulator messages using on-screen-display

mupen64plus-video-glide64mk2

hires	Support hi-resolution textures (requires dev-libs/boost)

pcsx2

clang	Use Clang compiler to build (the only compiler that is currently supported by upstream on Linux, do not report bugs if force-disabled)
sndio	Enable support for the media-sound/sndio backend

ppsspp

discord	Enable interfacing with a locally running Discord desktop client

rmg

angrylion-plugin	Enable the mupen64plus-video-angrylion-plus XMAME licensed plugin
discord	Enable Discord RPC support
dynarec	Enable the new dynarec for the mupen64plus-core plugin
rust-plugin	Enable the mupen64plus-input-gca rust plugin

snes9x

libretro	Build libretro port
netplay	Enable playing ROMs over the network (not recommended)

vbam

link	Enable GBA linking functionality

games-engines

devilutionx

sodium	Enable network packet encryption using dev-libs/libsodium
zerotier	Enable ZeroTier for online public games

exult

fluidsynth	Compile with support for FluidSynth
tools	Enable tools, usercode compiler and mods support

fheroes2

tools	Install development tools like 82m2wav and xmi2midi.

frobtads

tads2compiler	Build TADS2 compiler
tads3compiler	Build TADS3 compiler

love

gme	Use media-libs/game-music-emu to support additional music formats

minetest

client	Build Minetest client
leveldb	Enable LevelDB backend
prometheus	Enable prometheus client support
redis	Enable redis backend via dev-libs/hiredis
server	Build Minetest server
spatial	Enable SpatialIndex AreaStore backend

odamex

client	Build client target
hidpi	Use bundled FLTK 1.4, which has better support for HiDPI screens
master	Build master server target (advertises odamex server list)
odalaunch	Build the wxWidgets based launcher
portmidi	Enable PortMidi support
server	Build server target

openmw

devtools	Install development tools like bsatool, esmtool and opencs.
osg-fork	Use OpenSceneGraph forked by OpenMW instead of upstream OSG.

scummvm

fluidsynth	compile with support for fluidsynth
fribidi	Support for right-to-left languages via dev-libs/fribidi
mpeg2	enable mpeg2 codec for cutscenes
net	enable cloud support via media-libs/sdl2-net
sndio	Enable support for MIDI music using media-sound/sndio
unsupported	enable unsupported and/or broken game engines (you're on your own)

scummvm-tools

tremor	Enable tremor, a fixed-point version of the Ogg Vorbis decoder

solarus

doc	Install doxygen developer documentation.

games-fps

alienarena

vidmode	Link against x11-libs/libXxf86vm. Required for full-screen support.

chocolate-doom

midi	basic support for MIDI files

darkplaces

cdsound	Enables using CD audio in the engine
demo	Uses the demo data from quake1 (quake1-demodata)
lights	Install and setup the updated light maps
textures	Install and setup the updated textures

doomsday

demo	Install launcher dor doom1.wad from games-fps/doom-data
display-mode	Include the ability to set the display mode
fluidsynth	Build the FluidSynth sound driver
freedoom	Install launcher for doom1.wad from games-fps/freedoom
tools	Build additional tools such as doomsday-shell, md2tool and texc

duke3d-data

demo	Extract data files from the shareware version.
gog	Extract data files from the GOG.com version.

eduke32

duke3d	Install the Duke Nukem 3D data files, provided by games-fps/duke3d-data.
fluidsynth	Install media-libs/sdl2-mixer with fluidsynth support.
hrp	Install the Duke Nukem 3D High Resolution Pack.
offensive	Install the Duke Nukem 3D XXX Pack.
opl	Install the Duke Nukem 3D OPL music files.
psx	Install the Duke Nukem 3D PSX high resolution voice files.
sc-55	Install the Duke Nukem 3D Roland SC-55 music files.
sdk	Install the SDK files.
server	Enable support for multiplayer.
tools	Install the support tools for mapster32.
voidsw	Enable support for Shadow Warrior (Classic) through VoidSW.
voxels	Install the Duke Nukem 3D Voxels Pack.
vpx	Enable support for media-libs/libvpx.
xmp	Enable support for media-libs/exempi.

gzdoom

non-free	Enable non-free components
swr	Enable software renderer

nexuiz

maps	Install the community map pack

prboom-plus

dumb	Enable support for various tracker-style music formats via media-libs/dumb
fluidsynth	Enable support for MIDI via media-sound/fluidsynth
net	Enable support for network play
portmidi	Enable support for MIDI via media-libs/portmidi
sdl2-image	Enable support for high-resolution texture support via media-libs/sdl2-image
sdl2-mixer	Enable support for MIDI via media-libs/sdl2-mixer
server	Build PrBoom-Plus server

quake2-icculus

demo	Install the demo files (quake2-demodata) and configure for use
qmax	Build the pretty version (quake max)
rogue	Build support for the 'Ground Zero' Mission Pack (rogue)
xatrix	Build support for the 'The Reckoning' Mission Pack (xatrix)

quakeforge

client	Build Normal and QuakeWorld clients alongside the servers
wildmidi	Use media-sound/wildmidi for midi support

redeclipse

dedicated	Install only as a dedicated game server

rott

demo	Install the shareware version

sauerbraten

server	Compile server support

serioussam

alsa	Enable support ALSA sound.
pipewire	Enable support for pipewire.
vulkan	Enable support Vulkan render.

turtlearena

mumble	Adds player-location (positional audio) support to VoIP
server	Build server target
voice	Adds VoIP support

urbanterror

altgamma	Alternative way for gamma setting with modesetting driver
client	Build binary for client (includes code for non-dedicated server)
mumble	Use Mumble for ingame VoIP (experimental)
server	Build binary for dedicated server
skeetshootmod	Build support for skeetshoot mod for specific maps
voip	Use ioq3 ingame VoIP (experimental)

worldofpadman

maps	Install extra maps (PadPack)

xonotic

ode	Enable support for physics engine from dev-games/ode

yamagi-quake2

client	Build client
ctf	Build support for the 'Capture The Flag' addon
gles	Build GLES3 renderer
rogue	Build support for the 'Ground Zero' Mission Pack
softrender	Build software renderer
vulkan	Build experimental Vulkan renderer
xatrix	Build support for the 'The Reckoning' Mission Pack

games-kids

gcompris

kiosk	Enable kiosk mode by default (for use by small children or on a self-service host machine)

games-misc

ponysay

fish-completion	Enable fish completion support
non-free	Install non-free ponies (i.e. from the MLP franchise)

xcowsay

fortune	Enable support for fortune cookies via games-misc/fortune-mod

games-mud

tf

atcp	enable ATCP support.
gmcp	enable GMCP support.
option102	enable telnet option 102 support.

games-puzzle

gnome-tetravex

cli	Build the gnome-tetravex-cli command-line interface
gui	Build the gnome-tetravex graphical Gtk user interface

nightsky

bundled-libs	Use the upstream provided bundled libraries.

pingus

music	Enable playing of background music

tiny-and-big

bundled-libs	Use the upstream provided bundled libraries.

world-of-goo-gog

bundled-libs	Use bundled libs

world-of-goo-hb

bundled-libs	Use bundled libs

games-roguelike

FTL

bundled-libs	Use bundled libraries.

angband

sound	Enable and install sounds

stone-soup

advpng	Use alternate png optimization.
ncurses	Enable for console (uses ncurses) based build. (can be enabled on top of tiles)
tiles	Enable for graphical (tiled) build. (can be enabled on top of ncurses)

tomenet

client	Compile client
server	Compile server

games-rpg

daimonin-client

music	Install extra music

deponia-doomsday

bonus	Install the bonus content (Art Book, Concept Art, Soundtrack)

drascula

sound	Install optional audio files

dreamweb

doc	High-resolution scans of the written material in the original UK game box

freedroidrpg

devtools	Compile the additional dev tools
profile	Enable the integration of the ingame real-time profiler

hatoful-boyfriend

gui	Install the GUI for configuring screen resolution and input

hatoful-boyfriend-holiday-star

gui	Install the GUI for configuring screen resolution and input

kqlives

cheats	Enable cheating mode

manaplus

mumble	Enable support for voice chat
pugixml	Use dev-libs/pugixml for XML parsing isntead of dev-libs/libxml2
sdl2	Use libsdl2 instead of libsdl

the-longest-journey

hd	Install high definition backgrounds and sprites
hd-fmv	Install upscaled full motion videos

to-the-moon

bundled-libs	Use bundled libraries

games-simulation

corsix-th

midi	Adds support for background MIDI music via SDL_mixer
tools	Build tools for decoding RNC files

flightgear

dbus	Enable screensaver DBus interaction
gdal	Enable alternative terrain engine based on pagedLOD using sci-libs/gdal
qt5	Build Qt5 launcher application
udev	Enable event-based Input devices through virtual/udev
utils	Build various utilities (fgpanel, fgviewer among others)

openrct2

scripting	Enable the dev-lang/duktape scripting engine for executing user scripts.

openttd

allegro	Add support for Allegro
dedicated	Build only the openttd server, and not the client.
fluidsynth	Compile with support for FluidSynth
lzo	Enables LZO compression for savegames. This is only needed to load extremely old savegames. (versions before 0.2)
openmedia	Enables the free open media sets: OpenGFX, OpenSFX, OpenMSX, removing the requirement for proprietary TTD assets to play OpenTTD.

simutrans

midi	support for background MIDI music via media-sound/fluidsynth
minimal	Don't install any PakSets (scenario data)

simutrans-paksets

128	Install higher resolution scenario data (128 px graphics)
comic192	Install comic-like scenario data (192 px graphics)
cs128	Install Czech-Slovak scenario data (128 px graphics)
excentrique48	Install eccentric scenario data (48 px graphics)
german128	Install German scenario data (128 px graphics)
nippon64	Install Nippon scenario data (64 px graphics)

train-valley

gui	Install the GUI for configuring screen resolution and input

games-sports

speed-dreams

osggraph	Enable the new work-in-progress 3D engine using dev-games/openscenegraph
webstats	Enable support for sending racing statistics to a web server (experimental)

xmoto

double-precision	more precise calculations at the expense of speed

games-strategy

0ad

editor	Include Atlas scenario editor projects
lobby	Enable the use of net-libs/gloox and the multiplayer lobby
nvtt	Support for some uncompressed data formats (might be needed for some mods)

colobot

devbuild	TODO
tools	Build tools

colobot-data

music	Enable music support

freeciv

gtk3	Build the gtk3 client
gtk4	Build the gtk4 client
json	Add support for JSON via dev-libs/jansson
mapimg	Additional mag image toolkit via media-gfx/imagemagick
modpack	Build the freeciv-modpack-program to download/install mods
rule-editor	Build ruleset editor
server	Enable server support. Disabling this will also make it impossible to start local games.
sound	Add support for sound provided by media-libs/sdl-mixer
system-lua	Use dev-lang/lua instead of the bundled liblua
web-server	Build the freeciv-web server in place of the freeciv server

freeorion

client	Build game client

freesynd

devtools	Build development tools

hedgewars

server	Enable local server

ja2-stracciatella

editor	Adds necessary file to run the editor
ru-gold	Support for russian gold ja2 version

megaglest

editor	Build map editor
fribidi	Enable FriBIDi support
model-viewer	Build model viewer
streflop	Use the library streflop. Out of synchs may occur if not enabled.
tools	Build model import/export tools
unicode	Use unicode strings for wxwidgets
wxuniversal	Use the wxUniversal port which implements the various GUI controls by drawing them itself

satellite-reign

gui	Install the GUI for configuring screen resolution and input

ufoai

client	Build the main game client
server	Build the dedicated server

uqm

music	download and install original 3DO music files
remix	download and install remixed music files (large)
voice	download and install voice files (large)

wargus

bne	Support extracting data from the Battle.net Edition

warzone2100

discord	Enable Discord presence/join integration

wesnoth

server	Enable compilation of server

games-util

gslist

web	Enable the web interface

heroic-bin

gamescope	Run Heroic Launcher inside gamescope

lgogdownloader

gui	Enable GUI login support for passing reCAPTCHA

sc-controller

trayicon	Enable system tray icon

slade

fluidsynth	Enable MIDI software synthesis using media-sound/fluidsynth

wit

fuse	Enable image mount support via fuse

gnome-base

gdm

bluetooth-sound	Allow loading of bluetooth sound modules. This may be necessary for accessibility screen readers, but may cause bluetooth sound issues for users logging in.
fprint	Enables experimental fingerprint authentication using sys-auth/fprintd
plymouth	Enable support for smooth transition from sys-boot/plymouth

gnome

classic	Install gnome-extra/gnome-shell-extensions for the Gnome Shell Classic mode
extras	Install additional GNOME applications

gnome-applets

tracker	Build the tracker search bar applet

gnome-control-center

gnome-online-accounts	Enable configuration panel for net-libs/gnome-online-accounts accounts
ibus	Enable support for enhanced input methods through app-i18n/ibus

gnome-extra-apps

games	Install Gnome Games
share	Install the gnome-extra/gnome-user-share personal file sharing tool
shotwell	Install the media-gfx/shotwell photo manager
tracker	Install the app-misc/tracker indexer and the GNOME packages that require it

gnome-keyring

ssh-agent	Use GNOME Keyring to unlock SSH keys. Recommended unless you are using ECDSA or Ed25519 keys.

gnome-light

gnome-shell	Install gnome-base/gnome-shell and x11-wm/mutter for the standard GNOME 3 desktop mode

gnome-session

elogind	Support sys-auth/elogind for session tracking

gnome-settings-daemon

elogind	Rely on sys-auth/elogind as runtime logind provider
modemmanager	Enable WWAN support via net-misc/modemmanager
systemd	Rely on sys-apps/systemd as runtime logind provider

gnome-shell

elogind	Use sys-auth/elogind for session tracking and suspend support.
ibus	Enable support for enhanced input methods through app-i18n/ibus
pipewire	Use pipewire to enable the camera monitor

gvfs

afp	Enables support for accessing AFP (Apple Filing Protocol) network shares
archive	Enables support for accessing files in archives transparently via app-arch/libarchive
bluray	Enable playback of Blu-ray filesystems using media-libs/libbluray
elogind	Use sys-auth/elogind for session tracking.
fuse	Enables fuse mount points in $HOME/.gvfs for legacy application access
gnome-online-accounts	Enable configuration panel for net-libs/gnome-online-accounts accounts
google	Enables support for accessing Google accounts via dev-libs/libgdata
http	Enable the HTTP/DAV backend using net-libs/libsoup
nfs	Enable NFS client support via net-fs/libnfs.
udev	Enable udev base replacement code for cdda feature

libgnomecanvas

glade	Enable glade support

librsvg

tools	Build svg viewer tool

nautilus

cloudproviders	Enable the cloudproviders support
gstreamer	Enable the Audio/Video file properties page
previewer	Use gnome-extra/sushi to preview files from the file mananger
sendto	Enable the nautilus-sendto extension to send files to various locations/devices

gnome-extra

cinnamon

internal-polkit	Use Cinnamon's internal polkit agent instead of gnome-extra/polkit-gnome. This does not currently support multi-user fast switching.

cinnamon-control-center

modemmanager	Enable support for mobile broadband devices using net-misc/modemmanager

cjs

sysprof	Enable profiling data capture support using dev-util/sysprof-capture

eiciel

nautilus	Build gnome-base/nautilus extension

evolution-data-server

berkdb	sys-libs/db support needed to migrate old (pre-3.13 evolution versions) addressbook data
gnome-online-accounts	Enable net-libs/gnome-online-accounts based Google authentication support
oauth-gtk3	Enable internal OAuth2 authentication for GTK+3 applications (libedataserverui-*.so) support for Google and Outlook.com. If gnome-online-accounts is enabled and used, this is not necessary, but both can be supported at the same time with different setup at runtime
oauth-gtk4	Enable internal OAuth2 authentication for GTK 4 applications (libedataserverui4-*.so) support for Google and Outlook.com. If gnome-online-accounts is enabled and used, this is not necessary, but both can be supported at the same time with different setup at runtime
sound	Sound notification support through media-libs/libcanberra-gtk3 (does nothing without USE=gtk)
weather	Enable optional weather calendar support

gnome-commander

gsf	Add metadata support for OLE, OLE2 and ODF
pdf	Add metadata support for PDF
taglib	Add metadata support for ID3, Vorbis, FLAC and APE

gnome-contacts

gnome-online-accounts	Enable net-libs/gnome-online-accounts based Google authentication support

gnome-network-displays

firewalld	Install firewalld zones

gnome-shell-extension-gsconnect

nautilus	Install Nautilus extension for sending files via GSConnect

gnome-software

firmware	Enable firmware update support through sys-apps/fwupd
flatpak	Enable support for flatpak applications using sys-apps/flatpak
snap	Enable support for snap packages using app-containers/snapd
sysprof	Enable profiling data capture support using dev-util/sysprof-capture

gnome-system-monitor

systemd	Display sys-apps/systemd metadata, e.g. unit names, for running processes

libgda

canvas	Enable support for x11-libs/goocanvas
http	Enable embedded net-libs/libsoup based server
json	Enable support for JSON format
mdb	Enable support for Microsoft Access database using app-office/mdbtools
sourceview	Enable support for x11-libs/gtksourceview

libgsf

gtk	Enable use of gdk in thumbnailer

nemo

tracker	Add support for app-misc/tracker search

nm-applet

modemmanager	Enable support for mobile broadband devices using net-misc/modemmanager
teamd	Enable teamd configuration editor

gnustep-apps

gemas

projectcenter	Build and install plugin for gnustep-apps/projectcenter

gworkspace

gwmetadata	Enable the metadata indexing and searching system

sogo

activesync	Build the ActiveSync support code
sodium	Enable support for Argon2 password schemes using dev-libs/libsodium

gnustep-base

gnustep-back-art

xim	Enable X11 XiM input method

gnustep-back-cairo

xim	Enable X11 XiM input method

gnustep-back-xlib

xim	Enable X11 XiM input method

gnustep-make

libobjc2	Enables use of the GNUstep Objective-C runtime (gnustep-base/libobjc2) with non-fragile ABI and sys-devel/clang compiler
native-exceptions	Enables use of the native Objective-C exception support (@try/@catch/@finally) built-in objective-c exceptions with compilers that support it

gui-apps

foot

grapheme-clustering	Enable grapheme clustering support

grim

jpeg	Enable JPEG support.

gtkgreet

layershell	Enable layer shell support

kanshi

varlink	Enable remote control with varlink

mako

icons	Enable support for icons

swaybg

gdk-pixbuf	Support image types other than PNG

swayidle

elogind	Enable support for rootless session via elogind

swaylock

gdk-pixbuf	Enable additional image format support via the x11-libs/gdk-pixbuf library

waybar

evdev	Enable libevdev support for evdev related features
experimental	Enable experimental features, such as Bluetooth battery reporting
libinput	Enable libinput support for libinput related features
logind	Enable support for logind (bluetooth and idle inhibit)
mpd	Enable support for the Music Player Daemon
mpris	Enable support for mpris
network	Enable libnl support for network related features
pipewire	Enable support for pipewire
pulseaudio	Enable support for volume control via PulseAudio
sndio	Enable support for volume control via sndio
tray	Enable support for tray
wifi	Enable support for wifi/rfkill

waypipe

dmabuf	Use DMABUFs for data exchange and hardware decoding
ffmpeg	Link with ffmpeg to allow buffer displays using video streams
systemtap	Enable SystemTap/DTrace tracing

wayvnc

gbm	enable GPU-side screencopy (experimental)
tracing	Trace kernel and memory calls

wf-recorder

pipewire	Enable support for audio capture via media-video/pipewire.
pulseaudio	Enable support for audio capture via PulseAudio

gui-libs

gtk

broadway	Enable the GDK Broadway backend.
cloudproviders	Enable GtkPlacesSidebar to access cloud services
colord	Use x11-misc/colord for color management in printing
sysprof	Enable profiling data capture support using dev-util/sysprof-capture

gtksourceview

sysprof	Enable profiling data capture support using dev-util/sysprof-capture

libdecor

dbus	Enable dbus to query current cursor theme
examples	Build and install examples
gtk	Build GTK plugin

libhandy

glade	Install module and catalog for dev-util/glade

neatvnc

examples	Build and install examples
gbm	Enable support for the Generic Buffer Manager (gbm)
h264	Enable H.264 encoding
jpeg	Enable JPEG compression
tracing	Trace kernel and memory calls
websockets	Enable websockets support

vte

icu	Enable legacy charset support using dev-libs/icu
systemd	Support moving terminal child processes to their own systemd user scopes to avoid terminal getting killed due to child causing OOM

vte-common

systemd	Support moving terminal child processes to their own systemd user scopes to avoid terminal getting killed due to child causing OOM

wlroots

X	Enable support for X11 applications (XWayland)
drm	Enable Direct Rendering Management
libinput	Enable support for input devices via dev-libs/libinput
liftoff	Enable support for libliftoff KMS plane backend
session	Enable session support (is required for DRM and libinput)
x11-backend	Enable support for handling input/output devices through x11-libs/libxcb
xcb-errors	Better error reporting when using xwayland

xdg-desktop-portal-wlr

elogind	Enable support for rootless session via elogind

gui-wm

gamescope

libei	Enable emulated input using dev-libs/libei
pipewire	Enable screen capture via PipeWire
wsi-layer	Enable the WSI layer (required for HDR)

hyprland

legacy-renderer	Enable legacy renderer

sway

X	Enable support for X11 applications (XWayland)
swaybar	Install 'swaybar': sway's status bar component
swaynag	Install 'swaynag': shows a message with buttons
tray	Enable support for StatusNotifierItem tray specification
wallpapers	Install sway's default wallpaper image

wayfire

X	Enable support for X11 applications (XWayland).
gles3	Enable OpenGL ES 3.x Features.

kde-apps

akonadi

designer	Install plugin for dev-qt/designer
tools	Install tools for developers and testing
webengine	Enable support for system-wide defined KAccounts

analitza

eigen	Enable dev-cpp/eigen mathematical templates support

ark

zip	Enable ZIP archive support via dev-libs/libzip

cantor

R	Enable dev-lang/R backend support
julia	Enable dev-lang/julia backend support
qalculate	Enable sci-libs/libqalculate backend support

gwenview

activities	Enable kactivities support
fits	Enable support for NASA's sci-libs/cfitsio library
mpris	Enable support for MPRIS2 interface, requiring dev-qt/qtdbus as dependency.
share	Enable support for a share menu using kde-frameworks/purpose

k3b

webengine	Use dev-qt/qtwebengine for fancy k3bdiskinfoview

kalarm

pim	Enable birthday import, email functions etc. using kde-apps/akonadi

kalzium

editor	Enable the embedded molecule editor/viewer
solver	Enable the equation solver

kate-addons

filebrowser	Enable File System browser tool view
lspclient	Enable LSP (Language Server Protocol) client plugin
projects	Enable Project plugin for executing queries on SQL DBs
snippets	Enable Snippets Tool View plugin to manage or download code snippets
sql	Enable SQL plugin for executing queries on SQL DBs

kde-apps-meta

accessibility	Pull in kde-apps/kdeaccessibility-meta packages
admin	Pull in kde-apps/kdeadmin-meta packages
education	Pull in kde-apps/kdeedu-meta packages
games	Pull in kde-apps/kdegames-meta packages
graphics	Pull in kde-apps/kdegraphics-meta packages
multimedia	Pull in kde-apps/kdemultimedia-meta packages
network	Pull in kde-apps/kdenetwork-meta packages
pim	Pull in KDE PIM suite
sdk	Pull in developer-specific meta-packages
utils	Pull in kde-apps/kdeutils-meta packages

kdeadmin-meta

cron	Installs KDE application for virtual/cron configuration

kdecore-meta

share	Install kde-frameworks/purpose for share file context menu actions in kde-apps/dolphin
webengine	Enable www-client/falkon which depends on dev-qt/qtwebengine

kdeedu-meta

webengine	Enable packages requiring dev-qt/qtwebengine

kdegraphics-meta

color-management	Enable color management via media-libs/opencolorio
screencast	Pull in kde-apps/spectacle for screenshot/screenrecording support
webengine	Enable page scanning support via media-gfx/skanpage

kdemultimedia-meta

cdrom	Include packages for optical discs

kdenetwork-meta

bittorrent	Pull in net-p2p/ktorrent for BitTorrent protocol support
dropbox	Enable support for Dropbox in kde-apps/dolphin via kde-apps/dolphin-plugins-dropbox
samba	Enable support for net-fs/samba file sharing plugin from within file properties
screencast	Pull in kde-apps/krfb for Plasma desktop sharing support
webengine	Enable support for Google Drive integration via kde-misc/kio-gdrive

kdenlive

designer	Build plugins for dev-qt/designer

kdepim-addons

importwizard	Enable additional import plugins for kde-apps/akonadi-import-wizard
markdown	Enable Markdown support via app-text/discount

kdepim-meta

bogofilter	Install mail-filter/bogofilter for spam filter support in kde-apps/kmail
clamav	Install app-antivirus/clamav for virus detection support in kde-apps/kmail
spamassassin	Install mail-filter/spamassassin for spam filter support in kde-apps/kmail

kdesdk-meta

git	Enable support for Git VCS in kde-apps/dolphin via kde-apps/dolphin-plugins-git
mercurial	Enable support for Mercurial VCS in kde-apps/dolphin via kde-apps/dolphin-plugins-mercurial
subversion	Enable support for Apache Subversion VCS in kde-apps/dolphin via kde-apps/dolphin-plugins-subversion
webengine	Enable dev-util/kdevelop, requiring dev-qt/qtwebengine

kdeutils-meta

7zip	Install app-arch/p7zip for 7zip archive support in kde-apps/ark
gpg	Install kde-apps/kgpg which depends on kde-apps/akonadi
lrz	Install app-arch/lrzip for LRZ archive support in kde-apps/ark
rar	Install one of app-arch/rar, app-arch/unrar or app-arch/unar for RAR archive support in kde-apps/ark
webengine	Install app-editors/ghostwriter and kde-apps/kimagemapeditor, requiring dev-qt/qtwebengine

kget

bittorrent	Enable bittorrent transfer plugin through net-libs/libktorrent
gpg	Enable signature verification by GpgME++ via app-crypt/gpgme
mms	Enable MMS (Microsoft Media Server) plugin through media-libs/libmms

kig

geogebra	Support files created by sci-mathematics/geogebra-bin
scripting	Support Python scripting

kio-extras

X	Enable support for XCursor thumbnails via x11-libs/libX11
activities	Enable activities KIO worker and fileitem plugin
ios	Enable AFC (Apple File Conduit) KIO worker for iOS devices support
kf6compat	Disable components colliding with KF6, depend on KF6 components instead
man	Enable manpages KIO worker
nfs	Enable NFS support using net-libs/libtirpc
phonon	Enable file audio preview plugin using media-libs/phonon
sftp	Enable SFTP protocol support using net-libs/libssh
taglib	Enable audio thumbnails via media-libs/taglib

kleopatra

pim	Enable WKS publishing support using kde-apps/kmail

kmag

keyboardfocus	Enable keyboard focus tracking

konqueror

activities	Enable kactivities support

krdc

activities	Enable Plasma Activities support via kde-plasma/plasma-activities

ksystemlog

kdesu	Run as root using kdesu from kde-plasma/kde-cli-tools

ktouch

X	Enable support for X11 Keyboard Layout Detection

kwave

qtmedia	Enable playback via Qt5Multimedia

libkdepim

designer	Build plugins for dev-qt/designer

libkgapi

kf6compat	Disable components colliding with KF6, depend on KF6 components instead

libksane

kwallet	Enable encrypted storage of passwords with kde-frameworks/kwallet

mailcommon

designer	Build plugins for dev-qt/designer

marble

aprs	Enable support for APRS data sources
designer	Install plugin for dev-qt/designer
geolocation	Enable position information via dev-qt/qtpositioning
pbf	Enable OpenStreetMap PBF file support via dev-libs/protobuf
phonon	Enable sound support via media-libs/phonon
shapefile	Enable support for ESRI shapefiles
webengine	Use dev-qt/qtwebengine for embedded web browser

okular

crypt	Enable support for password-encrypted documents via kde-frameworks/kwallet
epub	Enable E-Book support via app-text/ebook-tools
markdown	Enable Markdown support via app-text/discount
mobi	Enable mobipocket support via kde-apps/kdegraphics-mobipocket
phonon	Enable sound support via media-libs/phonon
qml	Install Okular Qml components
share	Enable support for a share menu using kde-frameworks/purpose

parley

webengine	Build browser integration for the editor, requires dev-qt/qtwebengine

pimcommon

designer	Build plugins for dev-qt/designer

spectacle

share	Enable support for a share menu using kde-frameworks/purpose

step

qalculate	Enable the libqalculate library for unit conversion

thumbnailers

blender	Enable blender thumbnail generation using kde-frameworks/karchive
gettext	Enable PO file thumbnail generation using kde-apps/kdesdk-thumbnailers
mobi	Enable mobipocket thumbnail generation using kde-apps/kdegraphics-mobipocket
video	Enable video thumbnail generation using kde-apps/ffmpegthumbs

yakuake

absolute-position	Use kde-plasma/kwayland for absolute window positioning in KWin

kde-frameworks

kcompletion

designer	Build plugins for dev-qt/designer

kconfig

qml	Enable QML/QtQuick support via dev-qt/qtdeclarative

kconfigwidgets

designer	Build plugins for dev-qt/designer

kfilemetadata

epub	Enable support for reading EPUB ebook metadata
mobi	Enable mobipocket support via kde-apps/kdegraphics-mobipocket

kglobalaccel

kf6compat	Disable components colliding with KF6, depend on KF6 components instead

kguiaddons

kf6compat	Disable components colliding with KF6, depend on KF6 components instead

kiconthemes

designer	Build plugins for dev-qt/designer

kimageformats

eps	Support the EPS graphics file format

kinit

caps	Capabilities support for improved security and better OOM handling

kio

designer	Build plugins for dev-qt/designer
kwallet	Enable permanent storage of passwords for kpasswdserver with kde-frameworks/kwallet

kitemmodels

qml	Enable QML support via dev-qt/qtdeclarative

kitemviews

designer	Build plugins for dev-qt/designer

knewstuff

designer	Build plugins for dev-qt/designer
opds	Enable support for the Open Publication Distribution System via kde-frameworks/syndication

knotifications

phonon	Play notification sounds via media-libs/phonon instead of media-libs/libcanberra
qml	Enable QML support via dev-qt/qtdeclarative
speech	Enable text-to-speech notification support

knotifyconfig

phonon	Play notification sounds via media-libs/phonon instead of media-libs/libcanberra

kplotting

designer	Build plugins for dev-qt/designer

ktexteditor

editorconfig	Enable support for EditorConfig configuration files

ktextwidgets

designer	Build plugins for dev-qt/designer

kwallet

gpg	Support wallets with GnuPG encryption in addition to the default blowfish-encrypted file
kf6compat	Disable components colliding with KF6, depend on KF6 components instead

kwidgetsaddons

designer	Build plugins for dev-qt/designer

kxmlgui

designer	Build plugins for dev-qt/designer

networkmanager-qt

teamd	Enable Teamd control support

prison

qml	Enable QML/QtQuick support via dev-qt/qtdeclarative

purpose

kaccounts	Enable support for system-wide defined KAccounts
webengine	Enable support for system-wide defined KAccounts

sonnet

aspell	Enable the app-text/aspell spell-checking backend
designer	Build plugins for dev-qt/designer
hunspell	Enable the app-text/hunspell spell-checking backend
qml	Enable QML/QtQuick support via dev-qt/qtdeclarative

kde-misc

kdeconnect

X	Enable remote input mousepad plugin using x11-libs/libfakekey
pulseaudio	Enable system volume control plugin using media-libs/libpulse
telephony	Enable telephony plugin using kde-frameworks/modemmanager-qt

kio-gdrive

kf6compat	Disable components colliding with KF6, depend on KF6 components instead
share	Enable support for a share menu using kde-frameworks/purpose

krename

office	Enable support for file naming based on ODF metadata

tellico

bibtex	Add support for bibtex importing using btparse from dev-perl/Text-BibTeX
discid	Add support for reading disc IDs from audio CDs
yaz	Add support for searching Z39.50 databases

kde-plasma

discover

firmware	Enable support for firmware upgrades using sys-apps/fwupd
flatpak	Enable support for flatpak repositories using sys-apps/flatpak
snap	Enable support for snap packages using app-containers/snapd
webengine	Enable webflow support using dev-qt/qtwebview and dev-qt/qtwebengine instead of default URL handler

drkonqi

systemd	Enable Coredumpd integration

kde-cli-tools

kdesu	Build graphical frontend for kde-frameworks/kdesu

kdeplasma-addons

alternate-calendar	Support alternate calendar systems (currently Chinese or Indian) via dev-libs/icu
share	Enable applet for quickly sharing data to a variety of sources
webengine	Enable dictionary and web browser applets using dev-qt/qtwebengine

kinfocenter

usb	Show USB device information

ksystemstats

networkmanager	Enable improved backend for Network statistics using kde-frameworks/networkmanager-qt

kwin

lock	Enable screen locking via kde-plasma/kscreenlocker
screencast	Enable screencast portal using media-video/pipewire
shortcuts	Enable global shortcuts support via kde-plasma/kglobalacceld

plasma-desktop

ibus	Use ibus input method via app-i18n/ibus
scim	Enable applets that use app-i18n/scim
webengine	Build the OpenDesktop integration plugin

plasma-firewall

firewalld	Build net-firewall/firewalld backend
ufw	Build net-firewall/ufw backend

plasma-login-sessions

X	Install X11 session file for Display Managers (default is Wayland if both enabled)
wayland	Install Wayland session file for Display Managers

plasma-meta

browser-integration	Enable integration with Chrome/Firefox with browser extensions
colord	Enable kde-plasma/kwin color management via x11-misc/colord
crash-handler	Pull in kde-plasma/drkonqi for assisted upstream crash reports
crypt	Pull in kde-plasma/plasma-vault for encrypted vaults integration
discover	Pull in resources management GUI; a centralised GHNS alternative and optional sys-apps/fwupd frontend
display-manager	Pull in a graphical display manager
firewall	Pull in kde-plasma/plasma-firewall for system firewall administration
flatpak	Pull in kde-plasma/flatpak-kcm for flatpak permissions administration
grub	Pull in Breeze theme for sys-boot/grub
gtk	Enable Breeze widget style and system settings module for GTK+
kwallet	Enable support for KWallet auto-unlocking via kde-plasma/kwallet-pam
oxygen-theme	Pull in Oxygen icons, sound theme and visual style for KDE Plasma
plymouth	Pull in Breeze theme for sys-boot/plymouth
pulseaudio	Install Plasma applet for PulseAudio volume management
qt5	Pull in required packages for seamless integration of KF5/Qt5-based applications
sddm	Pull in the x11-misc/sddm display manager and system settings module
sdk	Pull in kde-plasma/plasma-sdk for Plasma development
smart	Pull in kde-plasma/plasma-disks for disk health monitoring
thunderbolt	Pull in kde-plasma/plasma-thunderbolt control center module
unsupported	Allow packages that are known to ruin runtime experience ** DO NOT FILE BUGS WITH THIS ENABLED **
wacom	Pull in kde-plasma/wacomtablet control center module
wallpapers	Install wallpapers for the Plasma Workspace
webengine	Use kde-apps/khelpcenter to access the locally installed KDE Help System Handbook
xwayland	Enable Wayland windows screensharing to XWayland applications via gui-apps/xwaylandvideobridge

plasma-nm

openconnect	Build support for the OpenConnect VPN client
teamd	Enable Teamd control support

plasma-workspace

appstream	Enable AppStream software metadata support
geolocation	Enables dataengine providing location information
policykit	Enable locale generation and Users KCM using sys-auth/polkit and sys-apps/accountsservice
screencast	Enable screencast portal using kde-plasma/kpipewire
telemetry	Enable User Feedback control module for kde-plasma/systemsettings
wallpaper-metadata	Show metadata for image wallpaper plugin using kde-apps/libkexiv2

powerdevil

brightness-control	Enable screen brightness control using app-misc/ddcutil
caps	Capabilities support for scheduled wakeup which can wake from suspend (CAP_WAKE_ALARM)

lxqt-base

liblxqt

backlight	Enable backlight control features.

lxqt-config

monitor	Build monitor settings tool
touchpad	Build touchpad settings tool

lxqt-meta

about	Install lxqt-base/lxqt-about
admin	Install lxqt-base/lxqt-admin
archiver	Install app-arch/lxqt-archiver
desktop-portal	Enable the LXQt sys-apps/xdg-desktop-portal backend implementation
display-manager	Install a graphical display manager
filemanager	Install x11-misc/pcmanfm-qt file manager
lximage	Install media-gfx/lximage-qt image viewer
minimal	Do not install x11-wm/openbox window manager
nls	Install dev-qt/qttranslations to better support different locales
powermanagement	Install lxqt-base/lxqt-powermanagement package
processviewer	Install x11-misc/qps package
screenshot	Install x11-misc/screengrab package
sddm	Install x11-misc/sddm display manager
ssh-askpass	Install lxqt-base/lxqt-openssh-askpass user password prompt tool
sudo	Install lxqt-base/lxqt-sudo
terminal	Install x11-terms/qterminal package
trash	Install gnome-base/gvfs to enable 'trash' functionality in x11-misc/pcmanfm-qt
window-manager	Install kde-plasma/kwin window manager

lxqt-panel

colorpicker	Build colorpicker plugin
cpuload	Build cpuload plugin
desktopswitch	Build desktopswitch plugin
directorymenu	Build directorymenu plugin
dom	Build dom plugin
kbindicator	Build kbindicator plugin
mainmenu	Build mainmenu plugin
mount	Build mount plugin
networkmonitor	Build networkmonitor plugin
quicklaunch	Build quicklaunch plugin
showdesktop	Build showdesktop plugin
spacer	Build spacer plugin
statusnotifier	Build statusnotifier plugin
sysstat	Build sysstat plugin
taskbar	Build taskbar plugin
tray	Build tray plugin
volume	Build volume plugin
worldclock	Build worldclock plugin

mail-client

aerc

notmuch	Enable support for net-mail/notmuch

alot

doc	Install user manual and API documentation

alpine

chappa	enhance Alpine by applying Eduardo Chappa's patches
onlyalpine	installs only the alpine binary, so it does not collied with pico and/or pine
passfile	Adds support for caching passwords into a file between sessions
smime	Enable support for S/MIME

balsa

rubrica	Adds support for rubrica addressbook
systray	Enable System Tray Icon support

claws-mail

archive	Enable archiving plugin
bogofilter	Build mail-filter/bogofilter plugin
libcanberra	Enable sound notification in connection with USE=notification
libnotify	Enable notification on the desktop in connection with USE=notification
litehtml	Enable dev-libs/gumbo html viewer plugin
notification	Notification for new mail in different way, see also USE flags libcanberra, libindicate and libnotify
oauth	Enable OAuth2 authentication support
pgp	Enable PGP support
python	Enable plugin for Python scripting
sieve	Build plugin for sieve filter support
smime	Build plugin for S/MIME support
spam-report	Enable plugin for spam reporting to various services
spamassassin	Build mail-filter/spamassassin plugin

evolution

archive	Enable archives support in attachments via app-arch/gnome-autoar
bogofilter	Build mail-filter/bogofilter plugin
geolocation	Enable support for displaying contacts on a map inside evolution using media-libs/libchamplain
highlight	Enable text highlighting plugin
ldap	Enable support for fetching contacts from an LDAP or Active Directory server using net-nds/openldap
libnotify	Enable desktop notifications through x11-libs/libnotify
sound	Enable sound notifications using media-libs/libcanberra-gtk3
spamassassin	Build mail-filter/spamassassin plugin
weather	Enable optional weather calendar support
ytnef	Enable optional TNEF attachments parser support using net-mail/ytnef

geary

ytnef	Enable optional TNEF attachments parser support using net-mail/ytnef

mutt

autocrypt	Enable autocrypt.org support
berkdb	Enable sys-libs/db database backend for header caching
gdbm	Enable sys-libs/gdbm database backend for header caching
gpgme	Build gpgme backend to support S/MIME, PGP/MIME and traditional/inline PGP
gsasl	Use GNU SASL via virtual/gsasl instead of Cyrus SASL (requires USE=sasl)
hcache	Enable header cache, one database backend needs to be enabled
lmdb	Enable dev-db/lmdb database backend for header caching
pgp-classic	Build classic_pgp backend to support PGP/MIME and traditional/inline PGP
pop	Enable support for POP3 mailboxes
smime-classic	Build classic_smime backend to support S/MIME
smtp	Enable support for direct SMTP delivery
tokyocabinet	Enable dev-db/tokyocabinet database backend for header caching

neomutt

asan	Enable Address sanitizer for debugging
autocrypt	Enable autocrypt.org support
berkdb	Enable BDB (Berkley DB) backend for header caching
gdbm	Enable GDBM (GNU dbm) backend for header caching
gpgme	Build gpgme backend to support S/MIME, PGP/MIME and traditional/inline PGP
kyotocabinet	Enable Kyoto Cabinet database backend for header caching
lmdb	Enable LMDB (Lightning Memory-Mapped Database) backend for header caching
lz4	Add lz4 support for header cache compression
notmuch	Enable support for net-mail/notmuch
pgp-classic	Build classic-pgp backend to support PGP/MIME and traditional/inline PGP
qdbm	Enable QDBM (Quicker Database Manager) database backend for header caching
smime-classic	Build classic-smime backend to support S/MIME
tokyocabinet	Enable Tokyo Cabinet database backend for header caching
ubsan	Enable undefined behavior sanitizer for debugging
zlib	Add zlib support for header cache compression
zstd	Add zstd support for header cache compression

roundcube

change-password	Allow users to change passwords through Roundcube
enigma	Add dependencies to support server-side GnuPG signing and/or encryption through the enigma plugin
fileinfo	Use the dev-lang/php fileinfo extension to guess the mime_type of attachments
ldap	Add dependencies to support connecting to an LDAP address book server

s-nail

kerberos	If network is enabled, this adds support for GSSAPI login on IMAP through virtual/krb5.
net	Enable support for network protocols (POP, IMAP and SMTP). If you only need to send mail with the local Transport Agent, disabling this will get you support for only /usr/sbin/sendmail call.
ssl	If network is enabled, this adds support for S/MIME and SSL/TLS-powered protocols through dev-libs/openssl.

thunderbird

clang	Use Clang compiler instead of GCC
eme-free	Disable EME (DRM plugin) capability at build time
hwaccel	Force-enable hardware-accelerated rendering (Mozilla bug 594876)
libproxy	Enable libproxy support
pgo	Add support for profile-guided optimization using gcc-4.5, for faster binaries. This option will double the compile time.
pulseaudio	Add sound server support via media-libs/libpulse (may be PulseAudio or Pipewire, or apulse if installed)
rust-extensions	Compile and install experimental rust extensions, that may become part of Thunderbird some day.
sndio	Enable support for the media-sound/sndio backend
system-av1	Use the system-wide media-libs/dav1d and media-libs/libaom library instead of bundled.
system-harfbuzz	Use the system-wide media-libs/harfbuzz and media-gfx/graphite2 instead of bundled.
system-icu	Use the system-wide dev-libs/icu instead of bundled.
system-jpeg	Use the system-wide media-libs/libjpeg-turbo instead of bundled.
system-libevent	Use the system-wide dev-libs/libevent instead of bundled.
system-librnp	Use system-wide dev-util/librnp instead of bundled one.
system-libvpx	Use the system-wide media-libs/libvpx instead of bundled.
system-png	Use the system-wide media-libs/libpng instead of bundled (requires APNG patches)
system-webp	Use the system-wide media-libs/libwebp instead of bundled.
wifi	Enable necko-wifi for NetworkManager integration, and access point MAC address scanning for better precision with opt-in geolocation services

mail-filter

MailScanner

exim	Set mail-mta/exim to used MTA
postfix	Set mail-mta/postfix to used MTA
spamassassin	Enable usage of mail-filter/spamassassin for spam protection

amavisd-new

courier	Add courier support
dkim	Add DomainKeys Identified Mail support
qmail	Add qmail support
razor	Add support for mail-filter/razor
rspamd	Add support for mail-filter/rspamd extension (HTTP only)
rspamd-https	Add support for mail-filter/rspamd extension (both HTTP and HTTPS)
spamassassin	Add support for mail-filter/spamassassin

bogofilter

tokyocabinet	Enable Tokyo Cabinet database support

dcc

rrdtool	Enable net-analyzer/rrdtool interface scripts

libmilter

poll	Use poll instead of select

maildrop

authlib	Add courier-authlib support
dovecot	Add dovecot authentication support
tools	Install maildirmake and deliverquota tools
trashquota	Count deleted messages as part of the maildir quota

mimedefang

poll	Use poll instead of select

opendkim

ldap	Enable openldap as a dataset facilitator or keys, determining domains to sign for, and any other dataset that opendkim supports.
lmdb	Add support for using dev-db/lmdb
lua	Enables control over signature verification, filtering and policy to be controlled by user defined lua scripts.
memcached	Add support for using dev-libs/libmemcached
opendbx	Use opendbx backend to facilitate dataset driven OpenDKIM configuration options like stats, bodylengthdb, etc. against a wide variety of database types
poll	Use poll() instead of select() for the provided asynchronous resolver library.
querycache	Add support for query caching (requires 'berkdb' flag)
sasl	Used to authenticate to a LDAP server in various ways if required.
stats	Add support for statistics (requires 'opendbx' flag)
unbound	Use the unbound dnssec library to perform DKIM DNS queries.

opendmarc

reports	Install the reports binaries: expire, import, reports, params
spf	Use the mail-filter/libspf2 for Sender Policy Framework checking

pyzor

gdbm	Enables the Gdbm back-end database engine for pyzord
mysql	Enables the MySQL back-end database engine for pyzord through dev-python/mysqlclient.
pyzord	Enable the pyzord server daemon
redis	Enables the redis back-end database engine for pyzord through dev-python/redis

rspamd

hyperscan	Enable hyperscan for fast regexp processing
jit	Enable PCRE JIT support

spamassassin

cron	Install a cron job to update SpamAssassin's rules daily.
qmail	Build qmail functionality and docs

mail-mta

courier

fax	Enables fax support in the courier mail server
norewrite	Prevents courier mail server from mangling virtual user addresses when sending
web	Enable the web interface
webmail	Enable the webmail interface

exim

arc	Adds support for Authenticated Receive Chain (ARC)
dane	Adds support for DNS-based Authentication of Named Entities
dcc	Adds support for Distributed Checksum Clearinghouse (DCC)
dkim	Adds support for DomainKeys Identified Mail (DKIM)
dlfunc	Install local_scan.h header to compile separate dlfunc libraries
dmarc	Adds support for DMARC
dnsdb	Adds support for a DNS search for a record whose domain name is the supplied query
dovecot-sasl	Adds support for Dovecot's authentication
dsn	Adds support for Delivery Status Notifications (DSN)
lmtp	Adds support for lmtp
mbx	Adds support for UW's mbx format
pkcs11	Require pkcs11 support in net-libs/gnutls with USE=gnutls
prdr	Adds support for Per-Recipient Data Response
proxy	Add support for being behind a proxy, such as HAProxy
redis	Adds support for querying dev-db/redis
spf	Adds support for Sender Policy Framework
srs	Adds support for Sender Rewriting Scheme
tdb	Use sys-libs/tdb for internal database storage (such as hints database)
tpda	Adds support for Transport Post-Delivery Actions

msmtp

daemon	Build/install msmtpd MTA daemon
mta	Enable this to install as system-wide MTA

netqmail

gencertdaily	Generate SSL certificates daily instead of hourly
highvolume	Prepare netqmail for high volume servers
pop3	Include POP3 server

notqmail

gencertdaily	Generate SSL certificates daily instead of hourly
highvolume	Prepare notqmail for high volume servers
pop3	Include POP3 server

opensmtpd

mta	Enable this to install as system-wide MTA

postfix

dovecot-sasl	Enable net-mail/dovecot protocol version 1 (server only) SASL implementation
eai	Add support for SMTPUTF8
ldap-bind	Add support for binding to LDAP backend using dev-libs/cyrus-sasl
lmdb	Add support for using dev-db/lmdb for lookup tables
memcached	Add support for using net-misc/memcached for lookup tables
mongodb	Add support for using dev-db/mongodb for lookup tables

qpsmtpd

postfix	create user with permissions for proper postfix interaction

ssmtp

mta	Install symlinks for sendmail-compatible MTA.

mate-base

caja

mate	Install x11-themes/mate-icon-theme which is needed when this package is used in the MATE desktop environment.

mate

base	Install base MATE Desktop applications that are recommended for the most common usage; for example, this installs the file manager. Disable this and other USE flags if you want a more minimal MATE Desktop.
extras	Install additional MATE Desktop applications that are recommended for extended usage of the MATE Desktop as upstream sees it; for example, this installs MATE Desktop's office related applications. Disable this if you plan to use your own non-MATE Desktop alternatives or a custom mixture of MATE and non-MATE packages.
help	Install gnome-extra/yelp to handle in application help menus and documentation browsing
notification	Force notification daemon to default to MATE's notification daemon. Enabled by default. Disable if it causes conflicts with other installed desktop environments.
themes	Install MATE Desktop's themes; if you use other themes, you can disable this to spare some space and time.

mate-applets

cpupower	Enable support for cpu frequency manipulation using sys-power/cpupower
netlink	Use dev-libs/libnl

mate-applets-meta

appindicator	Pull in mate-extra/mate-indicator-applet for AppIndicator applet
sensors	Pull in mate-extra/mate-sensors-applet for hw sensors applet

mate-control-center

accountsservice	Add support for AccountsService

mate-session-manager

gles2	Build with support for GLESv2 acceleration sessions

mate-settings-daemon

rfkill	build support for rfkill

mate-extra

caja-extensions

cdr	Add an extension to burn files to cds using app-cdr/brasero.
gajim	Add an extension to support net-im/gajim.
image-converter	Add image conversion support.
mail	Add an extension to support e-mail functionality.
media	Add video audio extension with totem.
open-terminal	Add an extension to support an open terminal.
pidgin	Add an extension to support net-im/pidgin
share	Add an extension to support sharing files.
wallpaper	Add an extension to support setting an image as the current wallpaper

mate-polkit

accountsservice	Support extraction of data from AccountsService

mate-power-manager

applet	Enable building of the MATE applet.

mate-system-monitor

wnck	Enable experimental support using x11-libs/libwnck.

mate-tweak

dropdown	Support the x11-terms/tilda dropdown terminal emulator

mate-utils

applet	Enable the mate dictionary applet

media-fonts

corefonts

tahoma	Also install the Tahoma font. Due to the lack of a free bold variant, this may render badly. See bug 184790.

culmus

ancient	Install ancient semitic scripts
fancy	Install fancy fonts
fontforge	Use media-gfx/fontforge to build fonts from source
taamey	Install taamey fonts

dejavu

fontforge	Use media-gfx/fontforge to build fonts from source

fonts-meta

emoji	Install a font supporting emojis
latin	Install additional latin fonts
ms	Install (free) fonts for the "ms" preset

intlfonts

bdf	Install BDF fonts in addition to PCF

iosevka

iosevka	Install the classic Iosevka font.
iosevka-aile	Install Iosevka Aile, a quasi-proportional sans-serif font.
iosevka-curly	Install Iosevka Curly, a curlier variant of Iosevka.
iosevka-curly-slab	Install Iosevka Curly Slab, the curly font, with slab-serifs.
iosevka-etoile	Install Iosevka Etoile, a quasi-proportional slab-serif font.
iosevka-slab	Install Iosevka Slab, a monospace slab-serif font.
iosevka-ss01	Install Iosevka SS01, an Iosevka variant made in the style of Andale Mono.
iosevka-ss02	Install Iosevka SS02, an Iosevka variant made in the style of Anonymous Pro Style.
iosevka-ss03	Install Iosevka SS03, an Iosevka variant made in the style of Consolas.
iosevka-ss04	Install Iosevka SS04, an Iosevka variant made in the style of Menlo.
iosevka-ss05	Install Iosevka SS05, an Iosevka variant made in the style of Fira Mono.
iosevka-ss06	Install Iosevka SS06, an Iosevka variant made in the style of Liberation Mono.
iosevka-ss07	Install Iosevka SS07, an Iosevka variant made in the style of Monaco.
iosevka-ss08	Install Iosevka SS08, an Iosevka variant made in the style of Pragmata Pro.
iosevka-ss09	Install Iosevka SS09, an Iosevka variant made in the style of Source Code Pro.
iosevka-ss10	Install Iosevka SS10, an Iosevka variant made in the style of Envy Code R.
iosevka-ss11	Install Iosevka SS11, an Iosevka variant made in the style of X Windows Fixed.
iosevka-ss12	Install Iosevka SS12, an Iosevka variant made in the style of Ubuntu Mono.
iosevka-ss13	Install Iosevka SS13, an Iosevka variant made in the style of Lucida.
iosevka-ss14	Install Iosevka SS14, an Iosevka variant made in the style of JetBrains Mono.
iosevka-ss15	Install Iosevka SS15, an Iosevka variant made in the style of IBM Plex Mono.
iosevka-ss16	Install Iosevka SS16, an Iosevka variant made in the style of PT Mono.
iosevka-ss17	Install Iosevka SS17, an Iosevka variant made in the style of Recursive Mono.
iosevka-ss18	Install Iosevka SS18, an Iosevka variant made in the style of Input Mono.

liberation-fonts

fontforge	Use media-gfx/fontforge to build fonts from source

montecarlo

bdf	Install BDF fonts in addition to PCF

mplus-outline-fonts

ipafont	Generates new fonts merged with media-fonts/ja-ipafonts

noto

extra	Install full upstream font set including condensed, semi-bold, extra-light variants

noto-emoji

icons	Install Noto Emoji icon theme

terminus-font

a-like-o	Changes view of letter 'a' - a looks like o (see homepage)
center-tilde	Place the '~' character vertically centered on the line instead of to the top.
distinct-l	ll2 variant with more distinctive l (lowercase L)
otf	Install Open Type Font (OTF) (required for HarfBuzz backend)
pcf-8bit	Install Portable Compiled Font (PCF) (X11 bitmap fonts), 8-bit encodings
pcf-unicode	Install Portable Compiled Font (PCF) (X11 bitmap fonts), Unicode encodings
psf	Install PC Screen Font (PSF) with unicode data (for linux console)
quote	Changes view of quotes: symmetric ` and ' instead of asymmetric one (see homepage)
ru-dv	Changes view of Russian letters 'de' and 've' (see homepage)
ru-g	Changes view of Russian letter 'ge' (see homepage)
ru-i	Changes view of Russian letter 'i' - not like Latin u, but like "mirrored" N (see homepage)
ru-k	Changes view of Russian letter 'k' (see homepage)

unifont

fontforge	Use media-gfx/fontforge to build fonts from source
utils	Install unifont utilities

media-gfx

ahoviewer

plugins	Build plugin support for now, in future pull additional plugins
rar	Rar archive support
zip	Zip archive support

album

plugins	Install optional plugins
themes	Install optional themes

alembic

hdf5	Add support sci-libs/hdf5
test	Build and run the test-suite

asymptote

boehm-gc	Enables using the Boehm-Demers-Weiser conservative garbage collector
context	Enables support for ConTeXt format (dev-texlive/texlive-context)
curl	Enables running remote programs via net-misc/curl
lsp	Enables Language Server Protocol
offscreen	Enables off-screen rendering
sigsegv	Enables using dev-libs/libsigsegv

blender

alembic	Add support for Alembic through media-gfx/alembic.
bullet	Enable Bullet (Physics Engine).
collada	Add support for Collada interchange format through media-libs/opencollada.
color-management	Enable color management via media-libs/opencolorio.
cuda	Build cycles renderer with nVidia CUDA support.
cycles	Build cycles renderer (requires media-libs/openimageio and dev-libs/boost).
cycles-bin-kernels	Precompile the cycles render kernels for the CUDA/HIP/OneAPI backends, if they are enabled, at compile time. This makes it so that the user doesn't have to wait for the kernels to compile when they are used for the first time in Blender. If this option is not on, they will be built as needed at runtime.
dds	Adds DDS textures support to Blender.
embree	Use embree to accelerate certain areas of the Cycles render engine.
experimental	Build Experimental Blender Modules
fluid	Adds fluid simulation support via the built-in Mantaflow library.
headless	Build without graphical support (renderfarm, server mode only).
hip	Build cycles renderer with AMD HIP support.
nanovdb	Enable nanoVDB support in Cycles. Uses less memory than regular openVDB when rendering.
ndof	Enable NDOF input devices (SpaceNavigator and friends).
oidn	Enable OpenImageDenoiser Support
oneapi	Build OIDN with Intel oneAPI SyCL support
openimageio	Enable OpenImageIO Support
openpgl	Enable path guiding support in Cycles
opensubdiv	Add rendering support form OpenSubdiv from Dreamworks Animation through media-libs/opensubdiv.
openvdb	Enable openvdb for volumetric processing, like the voxel remesher. Also enables volumetric GPU preview rendering for Nvidia cards.
optix	Add support for NVIDIA's OptiX Raytracing Engine.
osl	Add support for OpenShadingLanguage scripting.
potrace	Add support for converting bitmaps into Grease pencil line using the potrace library.
pugixml	Enable PugiXML support (Used for OpenImageIO, Grease Pencil SVG export)
renderdoc	Build Blender with renderdoc support
tbb	Use threading building blocks library from dev-cpp/tbb.
vulkan	Add support for the experimental Vulkan viewport backend

chafa

tools	Build command-line tools

darktable

gamepad	Support using game controllers as input devices
geolocation	Enable geotagging support
kwallet	Enable encrypted storage of passwords with kde-frameworks/kwallet
lto	Enable link-time optimisations in the RawSpeed library
midi	Support using MIDI input devices such as Behringer X-Touch Mini, Arturia Beatstep or Korg nanoKONTROL2, as input devices
tools	Install tools for generating base curves and noise profiles

digikam

addressbook	Enable akonadi contact integration
imagemagick	Enable support for additional image formats such as XCF, FITS, HEIC etc.
lensfun	Enable support for media-libs/lensfun
panorama	Build the panorama plugin which requires media-gfx/hugin
semantic-desktop	Enable kde-frameworks/kfilemetadata support
video	Enable integrated video player

eog-plugins

map	Enable world map display using media-libs/libchamplain

eom

imagemagick	Use media-gfx/imagemagick as an external backend for the thumbnailer

exact-image

swig	Adds Swig support dev-lang/swig

exiv2

bmff	Add support for the ISOBMFF format
webready	Support reading metadata over the internet

fbida

X	Install the Motif based image viewer "ida"
fbcon	Install the framebuffer image viewer "fbi"
ghostscript	Install the framebuffer ghostscript viewer "fbgs"

fig2dev

ghostscript	Require app-text/ghostscript-gpl to export PDF an bitmap formats

fontforge

truetype-debugger	Enable truetype debugger in fontforge
woff2	Enable support for WOFF2 format

fotowall

webcam	Enable webcam support

freecad

addonmgr	Build the addon manager module for automatic handling of 3rd party addons
cloud	Build the Cloud workbench, to access cloud providers (mostly Amazon S3).
designer	Build and install the Qt designer plugin, so the FreeCAD widgets can be used from within designer.
fem	Build the FEM module and workbench which provides Finite Element Analysis (FEA) workflows
gui	Build FreeCAD with a Qt based GUI. If built without setting this USE flag, FreeCAD can be used in a headless mode, for server-side instances. The Python modules are available, without their GUI parts though, if this is unset.
idf	Build the IDF module to provide file exchange capabilities with IDF files
image	Build the image module and workbench for working with bitmap images
inspection	Build the inspection workbench which gives you specific tools for examination of shapes (experimental)
material	Build the material module and workbench to work with materials
netgen	Build support for the netgen mesher through media-gfx/netgen.
openscad	Build the OpenSCAD module for interoperability with OpenSCAD and repairing Constructive Solid Geometry (CSG) history
part-design	Build the part design module and workbench for build part shapes from sketches
path	Build the path module and workbench to procude G-Code instructions for CNC
pcl	Use external sci-libs/pcl for point clouds support.
points	Build the points module and workbench for working with point clouds
raytracing	Build the raytracing module and workbench for raytracing and rendering
robot	Build the robot module and workbench for studying robot movements
show	Build the show module, a helper module for visibility automation
smesh	Build the Salome SMESH module
surface	Build the surface module and workbench
techdraw	Build the techdraw module and workbench, a more advanced and feature-rich successor of the drawing workbench
tux	Build the Tux module

geeqie

ffmpegthumbnailer	Enable video thumbnail support with media-video/ffmpegthumbnailer
map	Enable items GPS map display

gimp

fits	Enable support for loading/exporting FITS images
vector-icons	Enable support for vector icons (experimental)

graphicsmagick

dynamic-loading	Compile graphicsmagick with dynamically loadable modules
fpx	Enable FlashPix support with media-libs/libfpx
q16	Set storage quantum size to 16 (~2*memory)
q32	Set storage quantum size to 32 (~5*memory)
zip	Build with dev-libs/libzip to support the OpenRaster (ORA) format.

graphviz

X	Builds unflatten, vimdot, builds plugin -Txlib, and enables support for x11 in various other modules (needs cairo)
devil	Enables DevIL output plugin -Tdevil
gtk2	Enables gtk+ output plugin -Tgtk (needs cairo)
gts	Enables support for GNU Triangulated Surface Library (required for sfdp to work)
lasi	Enables PostScript output via media-libs/lasi, for plugin -Tlasi (needs cairo)

gthumb

slideshow	Enable slideshow plugin

hugin

sift	automatically align images with media-gfx/autopano-sift-C

imagemagick

corefonts	Use media-fonts/corefonts which is required by some commands
fpx	Enable media-libs/libfpx support
hdri	Enable High Dynamic Range Images formats
lqr	Enable experimental liquid rescale support using media-libs/liblqr
pango	Enable Pango support using x11-libs/pango
q32	Set quantum depth value to 32
q8	Set quantum depth value to 8

imv

freeimage	Use media-libs/freeimage for additional image support

inkscape

cdr	Enable support for CorelDRAW files via media-libs/libcdr
dia	Enable DIA flow chart import via app-office/dia
inkjar	Enable support for OpenOffice.org SVG jar files
sourceview	Enable syntax highlighting support via x11-libs/gtksourceview
svg2	Enable support for new SVG2 features
visio	Enable support for Microsoft Visio diagrams via media-libs/libvisio
wpg	Enable support for WordPerfect graphics via app-text/libwpg

iscan-plugin-gt-f500

minimal	Install the firmware only, and not the plugin.

kphotoalbum

map	Enable map display support using kde-apps/marble
phonon	Enable media-libs/phonon video backend (known to crash on some video formats)
share	Enable support for a share menu using kde-frameworks/purpose
vlc	Enable media-video/vlc video backend (recommended for X11)

krita

color-management	Enable color management via media-libs/opencolorio
media	Enable sound support for animations via media-libs/mlt
mypaint-brush-engine	Enable MyPaint brush engine support media-libs/libmypaint
qtmedia	Enable sound support for animations via dev-qt/qtmultimedia
xsimd	Enable usage of SIMD instructions via dev-cpp/xsimd

librecad

tools	Build additional tool programs: tff2lff

luminance-hdr

fits	Enable support for the FITS format

mandelbulber

opencl	Enable GPU rendering support using OpenCL

meshlab

double-precision	Use double type instead of float type for scalars

netgen

logging	Enable logging through dev-libs/spdlog
opencascade	Enable OpenCASCADE support

nomacs

opencv	Build support for media-libs/opencv
plugins	Build officially support plugins

okularpart

epub	Enable E-Book support via app-text/ebook-tools
mobi	Enable mobipocket support via kde-apps/kdegraphics-mobipocket

openclipart

gzip	Compresses clip art using gzip

openscad

egl	Build using EGL instead of GLX
experimental	Enable experimental features
glx	Enable GLX to interface OpenGL and X11
gui	Enable or disable building of the GUI
hidapi	Build in support for HID-Class devices using dev-libs/hidapi
manifold	Enable Manifold render backend via sci-mathematics/manifold
mimalloc	Build using dev-libs/mimalloc as memory allocator
spacenav	Add support for space navigator devices through dev-libs/libspnav

openvdb

abi10-compat	Disables newer features to maintain compatibility with ABI10
abi11-compat	Disables newer features to maintain compatibility with ABI11
abi12-compat	Disables newer features to maintain compatibility with ABI12
abi8-compat	Disables newer features to maintain compatibility with ABI8
abi9-compat	Disables newer features to maintain compatibility with ABI9
alembic	Add support for Alembic through media-gfx/alembic.
ax	Build the OpenVDB AX module to perform custom manipulation of OpenVDB data via an expression language: AX
blosc	Allow using blosc compression via dev-libs/c-blosc
cuda	Enable support for CUDA in NanoVDB
nanovdb	A lightweight, header only, and GPU friendly version of VDB
numpy	Build pyopenvdb with support for dev-python/numpy
utils	Build utility binaries

photoqt

devil	Support additional image formats using media-libs/devil
freeimage	Support additional image formats using media-libs/freeimage
mpv	Support for video files using media-video/mpv

plantuml

ant-task	Provides classes used to manage PlantUML Ant task

potrace

metric	default to a4 paper size and metric measurement

povray

io-restrictions	POV-Ray's mechanism for control of I/O operations

pqiv

archive	Enable support for images in archives and cbX comic book files

pstoedit

emf	Enable media-libs/libemf support
pptx	Enable support for generating PowerPoint pptx files

qimgv

opencv	Enable HQ scaling via media-libs/opencv
video	Add support for gif/webm playback via libmpv

qrencode

png	Enable PNG output support in qrencode tool

renderdoc

qt5	Build and install the qrenderdoc GUI

shotwell

opencv	Enable face detection via media-libs/opencv

skanpage

ocr	Enable support for Optical Character Recognition via app-text/tesseract

solvespace

system-mimalloc	Use system dev-libs/mimalloc instead of vendored library

ueberzugpp

opencv	Use media-libs/opencv for additional image formats and OpenCL accelerated scaling
wayland	Enable wayland support (proper window positioning is only supported with some compositors)
xcb-errors	Use x11-libs/xcb-util-errors for better error reporting with X

xpaint

pgf	Support for loading PGF images

yafaray

fastmath	Enable mathematic approximations to make code faster
fasttrig	Enable trigonometric approximations to make code faster
opencv	Add support for media-libs/opencv image processing.

media-libs

a52dec

djbfft	Prefer D.J. Bernstein's library for fourier transforms

allegro

dumb	Enable media-libs/dumb module library support
physfs	Enable physfs support
vga	Enables the VGA graphics driver

alsa-lib

alisp	Enable support for ALISP (ALSA LISP) interpreter for advanced features.

alure

dumb	Enable media-libs/dumb module library support
fluidsynth	Enables Fluidsynth MIDI software synthesis

assimp

collada	Add support for Collada interchange format through media-libs/opencollada
samples	Build viewer library

aubio

double-precision	Compile in double precision mode.

avidemux-core

system-ffmpeg	Use the ffmpeg provided by the system.

avidemux-plugins

aften	Enable A/52 (AC-3) audio encoder support.
amr	Enable Adaptive Multi-Rate format support via media-libs/opencore-amr.
dcaenc	Enable DTS Coherent Acoustics audio encoder support via media-sound/dcaenc.
fdk	Adds support for encoding AAC using media-libs/fdk-aac.
fribidi	Enable unicode bidirectional algorithm support via dev-libs/fribidi.
twolame	Enable TwoLAME support via media-sound/twolame, an optimised MPEG Audio Layer 2 (MP2) encoder.
vpx	Enable WebM VP8 Codec SDK support via media-libs/libvpx.
x265	Enables HEVC support with media-libs/x265.

cal3d

16bit-indices	Enables use of 16bit indices

chromaprint

tools	Build and install fpcalc and fpcollect tools

clutter

gtk	Use gdk-pixbuf from x11-libs/gtk+ as image rendering backend

cogl

kms	Enable KMS support.
pango	Build cogl-pango library for x11-libs/pango integration

coin

exceptions	Compile with C++ exceptions
qch	Install API documentation in QCH format
qthelp	Build API documentation in QtHelp format

cubeb

sndio	Enable support for the media-sound/sndio backend

dav1d

10bit	Add support for building 10-bit and 12-bit AV1.
8bit	Add support for decoding 8-bit AV1.
xxhash	Enable dev-libs/xxhash support for hashing muxer

devil

allegro	Add support for Allegro

dumb

allegro	Add support for Allegro 4

embree

compact-polys	Enables double indexed poly layout.
ispc	Build Embree with support for ISPC applications.
raymask	Enables ray mask support.
ssp	When enabled, Embree compiles with stack protection against return address overrides. Stack protection will wield a minor performance decrease in return for higher security.
tbb	Use TBB instead of the built-in Embree tasking system.
tutorial	Enable to build Embree tutorials programs.

esdl

image	Enable image support

fcft

harfbuzz	Use media-libs/harfbuzz for grapheme and run shaping
libutf8proc	Use media-libs/harfbuzz and dev-libs/libutf8proc for run shaping

flickcurl

raptor	Use media-libs/raptor for proper RDF serializing

freetype

adobe-cff	Use Adobe CFF as default font-renderer
bzip2	Support bzip2 compressed PCF fonts.
cleartype-hinting	Bytecode hinting mode for TrueType fonts that activates subpixel hinting (a.k.a. ClearType hinting) by default
fontforge	Install internal headers required for TrueType debugger in media-gfx/fontforge (built with USE=truetype-debugger)
harfbuzz	Use media-libs/harfbuzz for auto-hinting OpenType fonts. WARNING: may trigger circular dependencies!
infinality	Enable infinality options for improved LCD filtering
utils	Install utilities and examples from ft2demos

freeverb3

forcefpu	Disable assembly code
plugdouble	Build plugins in double precision mode (default is float)

ganv

fdgl	Use experimental force-directed graph layout

gegl

lensfun	Enable support for media-libs/lensfun.
sdl2	Add support for Simple Direct Layer 2.0 (media-libs/libsdl2)
umfpack	Enable sparse solving via sci-libs/umfpack.

glew

egl-only	Enable EGL support and disable X11 support

glfw

wayland-only	Enable wayland support and disable X11 support

gmmlib

custom-cflags	Do not override user CFLAGS like -march, -msse and similar with lib defaults. Not tested by upstream.

grilo

playlist	Enable support for playlists through dev-libs/totem-pl-parser

gst-plugins-bad

bzip2	Enable bzip2 encoder/decoder plugin

gst-plugins-base

X	Enable ximagesink and xvimagesink plugins; build GLX platform support if USE=opengl is enabled; build x11 windowing system support if USE=egl is enabled
gbm	Enable Graphics Buffer Manager based EGL windowing system support (requires egl and at least one of gles or opengl)
gles2	Enable OpenGL library and plugin via GLESv2 API (requires egl)
ivorbis	Enable integer based vorbis decoder
opengl	Enable OpenGL library and plugin via desktop OpenGL API
pango	Enable pango GStreamer plugin
wayland	Enable Wayland EGL windowing system support (requires egl and at least one of gles2 or opengl)

gstreamer

unwind	Enable sys-libs/libunwind usage for better backtrace support in leaks tracer module

harfbuzz

experimental	Enable experimental APIs
glib	Enable dev-libs/glib unicode functions
graphite	Enable media-gfx/graphite2 complementary shaper

imlib2

X	Use the X window system
apidoc	Provide doxygen generated API docs
bzip2	Bzip2 loader support
eps	Eps image loader support
filters	Build filter functions (blur, sharpen, etc)
heif	Heif and Avif image loader support
mp3	ID3 loader support
packing	Enable structure packing. This will reduce memory footprint at the cost of unaligned memory access
shm	Use MIT shared memory support for X image transfer
text	Build text (TrueType font) functions
zlib	Zlib loader support

intel-mediasdk

tools	Build analyse and inspect tools

jasper

heif	Enable experimental support for HEIF/HEIC, unsupported by upstream

leptonica

utils	Install command-line utilities

lib3mf

system-act	Use system-provided dev-go/act as code generator instead of package provided binaries. This flag will be removed after some time used for testing!

libafterimage

shaping	Use MIT shaped X windows extention.
shm	Use MIT shared memory extention for X image transfer.

libao

sndio	Add support for media-sound/sndio

libass

libunibreak	Use dev-libs/libunibreak for Unicode line breaking algorithm

libavif

aom	Enable support for the AOM codec encoding and decoding
dav1d	Enable support for the dav1d codec decoding
extras	Build extra apps (avifenc, avifdec) and test files
gdk-pixbuf	Build a gdk-pixbuf loader
rav1e	Enable support for the rav1e codec encoding
svt-av1	Enable support for the SVT-AV1 encoder

libbdplus

aacs	Add support for decryption of AACS

libbluray

aacs	Add support for decryption of AACS
bdplus	Use media-libs/libbdplus for BD+ decryption
java	Add support for BD-J
utils	Install command-line utilities and examples

libcanberra

alsa	Enables ALSA sound driver.
gstreamer	Enables gstreamer sound driver. Not useful when alsa or pulseaudio is available.
gtk2	Enables building of gtk+ helper library, gtk+ runtime sound effects and the canberra-gtk-play utility. To enable the gtk+ sound effects add canberra-gtk-module to the colon separated list of modules in the GTK_MODULES environment variable.
gtk3	Enables building of gtk+3 helper library, gtk+3 runtime sound effects and the canberra-gtk-play utility. To enable the gtk+3 sound effects add canberra-gtk-module to the colon separated list of modules in the GTK_MODULES environment variable.
pulseaudio	Enables PulseAudio sound driver that should be able to support positional event sounds. This is the preferred choice for best sound events experience and picked by default if compiled in and possible to use at runtime.
sound	Install x11-themes/sound-theme-freedesktop to get sounds on Gnome and Xfce.
tdb	Enables Trivial Database support for caching purposes.

libde265

dec265	Enable build of dec265 example program
enc265	Enable build of enc265 tool
sdl	Enable video output of dec265 example program with media-libs/libsdl
tools	Enable installation of varous binary tools

libffado

test-programs	Install standalone test programs

libggi

3dfx	Enables support for Voodoo chipsets, also called 3DFX and TDFX
vis	Enables sparc vis support for libggi

libgphoto2

serial	Enable serial port support

libgpod

gtk	Enable ArtworkDB support

libheif

aom	Use media-libs/libaom for AVIF encoding/decoding
gdk-pixbuf	Enable x11-libs/gdk-pixbuf plugin
go	Enable building dev-lang/go code/examples
rav1e	Use media-video/rav1e for AVIF encoding
svt-av1	Use media-libs/svt-av1 for SVT-AV1 encoding
webp	Enable high-quality YCbCr/RGB color space conversion algorithms
x265	Use media-libs/x265 for HEIF encoding

libjxl

gdk-pixbuf	Build a gdk-pixbuf loader.
jpeg	Enable full support for JPEG images. When disabled, only lossless conversion between JPEG and JPEG-XL is supported.

liblastfm

fingerprint	Build the lastfm-fingerprint library

libmp4v2

utils	Install command-line utilities

libmypaint

gegl	Add support for media-libs/gegl

libopenglrecorder

openh264	Enable H.264 support using media-libs/openh264
vpx	Enable VP8/VP9 codec support via media-libs/libvpx

libpagemaker

tools	Build command line file format conversion tools

libpano13

suitesparse	Use Sparse Levenberg Marquardt algorithm instead of dense Levenberg Marquardt algorithm

libplacebo

glslang	Use dev-util/glslang to compile GLSL
lcms	Add support for color management via media-libs/lcms
libdovi	Use media-libs/libdovi to read Dolby Vision metadata
shaderc	Use media-libs/shaderc to compile GLSL
xxhash	Use dev-libs/xxhash to speed up internal hashing

libpng

apng	support unofficial APNG (Animated PNG) spec

libprojectm

gles2	Provide support for OpenGL ES 2 and 3

libpulse

asyncns	Use libasyncns for asynchronous name resolution.
doc	Build the doxygen-described API documentation.
glib	Add support to dev-libs/glib-based mainloop for the libpulse client library, to allow using libpulse on glib-based programs.

libsdl

joystick	Control joystick support (disable at your own risk)
sound	Control audio support (disable at your own risk)
video	Control video support (disable at your own risk)

libsdl2

fcitx	Enable support for app-i18n/fcitx
gles1	include OpenGL ES 1.0 support
haptic	Enable the haptic (force feedback) subsystem
ibus	Enable support for app-i18n/ibus
joystick	Control joystick support (disable at your own risk)
kms	Build the KMSDRM video driver
pipewire	Enable support for the media-video/pipewire audio backend
sndio	Enable support for the media-sound/sndio backend
sound	Control audio support (disable at your own risk)
video	Control video support (disable at your own risk)

libshumate

sysprof	Enable sysprof-capture support for profiling

libtgvoip

dsp	Enable signal processing (echo cancellation, noise suppression, and automatic gain control)

libv4l

bpf	Enable support for IR BPF decoders
tracer	Build the v4l2-tracer tool and library
utils	Build the v4l-utils collection of utilities

libva-compat

drm	Enables VA/DRM API support.

libva-intel-driver

hybrid	Enable support for hybrid vaapi hardware acceleration on Intel Haswell and newer architectures

libva-intel-media-driver

redistributable	Install redistributable media kernel binaries (no source code) files (primarily needed for video encoding support)

libvisio

tools	Build conversion tools

libvmaf

embed-models	Compile default vmaf models into the library (needs app-editors/vim-core)

libvpl-tools

drm	Build with DRM support

libvpx

highbitdepth	Enable 10 and 12 bit support for VP9.
postproc	Enable additional post processing filters

libwebp

swap-16bit-csp	Enable byte swapping for 16 bit colorspace

libzmf

tools	Build conversion tools

lilv

tools	Build command line utilities

lsp-plugins

lv2	Build lv2 plugins
vst	Support LinuxVST plugins

lv2

plugins	Enables examples plugins.

lvtk

gtk2	Enable x11-libs/gtk+:2 based GUI support
tools	Compile and install ttl2c tool

mesa

d3d9	Enable Direct 3D9 API through Nine state tracker. Can be used together with patched wine.
llvm	Enable LLVM backend for Gallium3D.
lm-sensors	Enable Gallium HUD lm-sensors support.
opencl	Enable the Rusticl Gallium OpenCL state tracker.
osmesa	Build the Mesa library for off-screen rendering.
proprietary-codecs	Enable codecs for patent-encumbered audio and video formats.
vdpau	Enable the VDPAU acceleration interface for the Gallium3D Video Layer.
vulkan-overlay	Build vulkan-overlay-layer which displays Frames Per Second and other statistics
wayland	Enable support for dev-libs/wayland
xa	Enable the XA (X Acceleration) API for Gallium3D.

mesa-amber

gles1	Enable GLESv1 support.
wayland	Enable support for dev-libs/wayland

mlt

frei0r	Build the module for media-plugins/frei0r-plugins
opencv	Build motion tracking module using media-libs/opencv
python	Build SWIG bindings for Python
rtaudio	Builds rtaudio consumer for native audio support on multiple platforms
rubberband	Enable audio pitch-shifting using media-libs/rubberband
vidstab	Enabled video stabilization with media-libs/vidstab

netpbm

rle	Build converters for the RLE format (utah raster toolkit)

noise-suppression-for-voice

lv2	Enable the LV2 plugin
vst	Enable the VST plugin
vst3	Enable the VST3 plugin

oidn

apps	Build the standalone denoise, self test, and benchmark binaries.
hip	Build OIDN with AMD HIP support.
openimageio	Enable OpenImageIO Support

oneVPL-cpu

openh264	Use media-libs/openh264 instead of media-libs/x264

openal

pipewire	Enable support for the media-video/pipewire audio backend
sndio	Enable support for the media-sound/sndio backend

opencolorio

apps	Build the OCIO command line apps

opencv

atlas	Use sci-libs/atlas for blas, lapack and sparse blas routines
contrib	Install user contributed scripts from opencv_contrib (Experimental!)
contribcvv	Enable CVV in contrib (requires Qt5)
contribdnn	Enable DNN module contrib (requires tinydnn)
contribfreetype	Enable Drawing UTF-8 strings with media-libs/freetype&media-libs/harfbuzz
contribhdf	Enable HDF module (requires sci-libs/hdf5)
contribovis	Enable OGRE vision module support (dev-games/ogre)
contribsfm	Enable SFM module (requires USE="eigen gflags glog")
contribxfeatures2d	Enable xfeatures2d in contrib
cuda	Enable NVIDIA Cuda computations support (Experimental!)
cudnn	Enable support for nVidia cuDNN library
dnnsamples	Enable dnn caffeemodel samples
eigen	Enable usage of dev-cpp/eigen for computations
features2d	Enable features2d module
gdal	Enable support for sci-libs/gdal library
gflags	Use Google's C++ argument parsing library (dev-cpp/gflags)
glog	Use Google's C++ logging library (dev-cpp/glog)
gtk3	Enable x11-libs/gtk+:3 support
jasper	Use media-libs/jasper for jpeg2k support
mkl	Use sci-libs/mkl for blas, lapack and sparse blas routines
non-free	Enable non-free components
opencvapps	Enable compilation with opencvapps
quirc	Enable qrcode decoding via media-libs/quirc
tbb	Enable multithreading with the Intel Threads Building Block (dev-cpp/tbb)
tesseract	Use Google's OCR Engine
testprograms	Build and install programs for testing OpenCV (performance)
truetype	Enable media-libs/freetype support for gapi module
video_cards_intel	Enable Video Acceleration API for hardware decoding for Intel cards
vtk	Build new 3D visualization module viz based on sci-libs/vtk

openexr

large-stack	Enables code to take advantage of large stack support.
utils	Build several binary tools for verifying and manipulating EXR files.

openh264

plugin	Install the Gecko Media Plugin (GMP) for use with Mozilla packages
utils	Install the CLI encoder and decoder utilities

openimageio

dicom	Enable DICOM medical image file support via sci-libs/dcmtk
fits	Enable support for NASA's sci-libs/cfitsio library
gui	Build iv (with Qt5)
opencv	Enable OpenCV support via media-libs/opencv
openvdb	Enable OpenVDB support via media-gfx/openvdb
ptex	Enable Ptex texture mapping system file support via media-libs/ptex
qt6	Build iv with Qt6
tools	Build the command-line tools

opensubdiv

glew	Enable support for OpenGL Extension Wrangler Library (media-libs/glew)
glfw	Build all example files that uses (media-libs/glfw)
ptex	Adds support for faster per-face texture mapping through media-libs/ptex
python	Use dev-lang/python to process source and documentation source files
tbb	Enable multithreading with the Intel Threads Building Blocks through dev-cpp/tbb
tutorials	Install the tutorials

opus

custom-modes	Enable non-Opus modes, e.g. 44.1 kHz and 2^n frames
deep-plc	Enable Deep Packet Loss Concealment (PLC)
dred	Enable Deep REDundancy (DRED)
osce	Enable Opus Speech Coding Enhancement (OSCE)

opusfile

fixed-point	Enable fixed-point arithmetic operations
float	Enable floating point arithmetic operations
http	Enable http connections

osl

gui	Build the osltoy binary (with Qt5)
libcxx	Build against sys-libs/libcxx when using clang
nofma	Do not use Fuse-Multiply-Add operations
optix	Add support for NVIDIA's OptiX Raytracing Engine
partio	Use media-libs/partio
qt6	Build the osltoy binary (with Qt6)

phonon

designer	Install plugin for dev-qt/designer

portmidi

test-programs	Install various example programs

quarter

designer	Install plugin for dev-qt/designer
qch	Install API documentation in QCH format
qthelp	Build API documentation in QtHelp format

quirc

opencv	Build tools requiring media-libs/opencv (inspect-opencv,quirc-demo-opencv)
sdl	Build tools requiring media-libs/sdl-gfx (inspect, quirc-demo)
tools	Build tools (qrtest)
v4l	Build tools for webcams (quirc-scanner)

raptor

json	Enable support for JSON parsing

raspberrypi-userland-bin

hardfp	Use armv6 hardfp ABI

roc-toolkit

tools	Install helper tools like roc-conv, roc-recv, roc-send

rubberband

jni	Enables building of Java Native Interface library
lv2	Add support for Ladspa V2
programs	Builds also executable applications
vamp	Enables vamp plugins support (Audio analysing plugins)

sdl-mixer

fluidsynth	Use media-sound/fluidsynth for MIDI support
midi	basic support for MIDI files
mod	basic support for MOD files
playtools	Install playwave and playmus tools (useful for testing)
smpeg	Use media-libs/smpeg for MP3 support
wav	support WAVE files

sdl2-mixer

fluidsynth	Use media-sound/fluidsynth for MIDI support
midi	basic support for MIDI files
mod	basic support for MOD files
playtools	Install playwave and playmus tools (useful for testing)
tremor	enable OGG Vorbis music via libtremor
wav	support WAVE files

sdl2-ttf

harfbuzz	Use media-libs/harfbuzz for enhanced font rendering

sdl_audiolib

fluidsynth	Enable support for MIDI via media-sound/fluidsynth
mpg123	Enable support for mp3 decoding via media-sound/mpg123
openmpt	OpenMPT decoder via media-libs/libopenmpt
soxr	Enable SoX Resampler support via media-libs/soxr
wildmidi	Enable support for MIDI via media-sound/wildmidi

sge

image	enable sdl-image support

spandsp

fixed-point	Enable fixed point support

speex

utils	Enables speex commandline utilities (speexenc, speexdec).
vbr	Enable VBR support.

suil

gtk2	Enable GTK2 based GUI support

svgalib

kernel-helper	Build the helper kernel module

tremor

low-accuracy	enable 32bit only multiply operations

urt

tools	Install tools

vips

archive	Enable support for compressed files using app-arch/libarchive
deprecated	Enable deprecated components
fits	Enable support for the Flexible Image Transport System data format using sci-libs/cfitsio
highway	Enable SIMD optimizations using dev-cpp/highway (replaces USE=orc)
imagequant	Enable support for Image Quantization using media-gfx/libimagequant
matio	Enable support for matlab files using sci-libs/matio
pango	Enable support for text rendering using x11-libs/pango

vulkan-loader

layers	Include the vulkan layers

waffle

wayland	Enable Wayland support

x264

interlaced	enable interlaced encoding support, this can decrease encoding speed by up to 2%
pic	disable optimized assembly code that is not PIC friendly

x265

10bit	Add support for producing 10bits HEVC.
12bit	Add support for producing 12bits HEVC.
numa	Build with support for NUMA nodes.

xine-lib

bluray	Enable playback of Blu-ray filesystems using media-libs/libbluray
dav1d	Enable support for media-libs/dav1d AV1 decoder
dxr3	Enable support for DXR3 mpeg acceleration cards.
flac	Build the media-libs/flac based FLAC demuxer and decoder. This flag is not needed for playing FLAC content, neither standalone nor in Ogg container (OggFLAC), but might have better support for exotic features like 24-bit samples or 96kHz sample rates.
gtk	Build the gdkpixbuf-based image decoder plugin.
imagemagick	Build the ImageMagick-based image decoder plugin.
mad	Build the media-libs/libmad based mp3 decoder. This mp3 decoder has superior support compared to the one coming from FFmpeg that is used as a fallback. If you experience any bad behaviour with mp3 files (skipping, distorted sound) make sure you enabled this USE flag.
mmap	Use mmap() function while reading file from local disks. Using mmap() will use more virtual memory space, but leaves to the Kernel the task of caching the file's data. mmap() access should be faster, but might misbehave if the device where the file resides in is removed during playback.
nfs	Allow accessing NFS shares via net-fs/libnfs.
sftp	Use net-libs/libssh2 to access SFTP servers.
truetype	Use media-libs/freetype for font rendering and media-libs/fontconfig for font discovery. Enabling this USE flag will allow OSD (such as subtitles) to use more advanced font and to more easily select which font to use. The support for TrueType fonts in xine-lib is still experimental, and might not be as good looking as the bitmap fonts used with this USE flag disabled.
vdr	Build the VDR plugin
vidix	Enable support for vidix video output.
vis	Adds support for SIMD optimizations for UltraSPARC processors.
vpx	Enable VP8 codec support via media-libs/libvpx.
xvmc	Enable support for XVideo Motion Compensation (accelerated mpeg playback).

xvid

pic	disable optimized assembly code that is not PIC friendly

zita-resampler

tools	Install zresample and zretune tools

zmusic

fluidsynth	Enable support for MIDI via media-sound/fluidsynth
mpg123	Enable support for MPEG audio playback via media-sound/mpg123

media-plugins

alsa-plugins

arcam_av	Enables Arcam AV control plugin
mix	Enables upmix and vdownmix plugin
usb_stream	Enables usb_stream plugin

audacious-plugins

ampache	Support controlling audacious via ampache
bs2b	Enable Bauer Bauer stereophonic-to-binaural headphone filter
cue	Support CUE sheets using the libcue library
fluidsynth	Support FluidSynth as MIDI synth backend
gme	Support various gaming console music formats
http	Support HTTP streams through neon
openmpt	Add support for OpenMPT
pipewire	Build the PipeWire output plugin
scrobbler	Build with scrobbler/LastFM submission support
soxr	Build with SoX Resampler support
speedpitch	Enable speed/pitch effects
streamtuner	Build the streamtuner plugin

calf

experimental	Enable experimental features/plugins
lv2	Add support for Ladspa V2

frei0r-plugins

facedetect	Enables building of facedetect plugin, which depends on media-libs/opencv
scale0tilt	Enables building of scale0tilt and vectorscope plugins, which depend on media-libs/gavl

gkrellmpc

threads	Use separate thread to init connection (unsafe)

grilo-plugins

chromaprint	Enable Chromaprint support
daap	Enable dmap support through net-libs/libdmapsharing
flickr	Enable Flickr support
freebox	Build support for viewing TV channels using Freebox
gnome-online-accounts	Enable net-libs/gnome-online-accounts support
thetvdb	Build support for thetvdb.com
tracker	Build support for content discovery using the app-misc/tracker indexer
youtube	Build support for YouTube content discovery using dev-libs/libgdata

gst-plugins-gtk

gles2	Enable gtkglsink OpenGL sink based on GLESv2 API
opengl	Enable gtkglsink OpenGL sink based on desktop OpenGL API

gst-plugins-meta

http	Enable http streaming via net-libs/libsoup
libvisual	Enable visualization effects via media-libs/libvisual
vpx	Enables vp8 codec support using libvpx, required to play some HTML5 videos

gst-plugins-vaapi

drm	Enable DRM renderer
gles2	Enable GLESv2 and GLESv3 support

imlib2_loaders

xcf	Enable XCF image loader

ir_lv2

tools	Build convert4chan tool

mpg123-output-plugins

int-quality	Use rounding instead of fast truncation for integer output, where possible

vdr-cdplayer

cdparanoia	Enable cdparanoia (audio CD ripper) support

vdr-dvbapi

dvbcsa	use media-libs/libdvbcsa free implementation of the DVB Common Scrambling Algorithm

vdr-epgsearch

conflictcheckonly	install the "conflictcheckonly" vdr-plugin
epgsearchonly	install the "epgsearchonly" vdr-plugin
quicksearch	install the "quicksearch" vdr-plugin
tre	Add support for unlimited fuzzy searching with help of dev-libs/tre library

vdr-streamdev

client	Compile the VDR plugin vdr-streamdev-client that can connect a vdr to a remote streamdev-server instance
server	Compile the VDR plugin vdr-streamdev-server that allows remote systems to access the vdr using streamdev-specific VTP and HTTP protocol

vdr-vdrmanager

stream	Add support for streaming Video to Android client

vdr-weatherng

dxr3	enables lower osd color depth for dxr3 cards

vdr-xineliboutput

bluray	Enable BluRay metadata support through media-libs/libbluray
cec	Enable CEC support through dev-libs/libcec
vdr	Compile the vdr output plugin to use local or remote xine as output
xine	Compile the xine input plugin for displaying vdr video and OSD

media-radio

ax25-tools

X	Enable some X based configuration tools.

chirp

radioreference	pull in optional deps for query of radioreference

direwolf

hamlib	Enables support by the Hamlib amateur radio rig control library

fldigi

hamlib	Enables support by the Hamlib amateur radio rig control library to get/set frequency and mode of the ham radio in use

svxlink

qt5	Build and install qtel application
rtlsdr	Add support for rtlsdr hardware

tucnak

hamlib	Enables support by the Hamlib amateur radio rig control library to get/set frequency and mode of the ham radio
rtlsdr	Add support for rtlsdr hardware

unixcw

ncurses	Enables building the curses based morse code tutor program 'cwcp'.

xastir

geotiff	Install geotiff support. Allows using USGS DRG topo maps or other types of geotiff mapes/images

media-sound

abcde

aiff	Enable support for Audio Interchange File Format (AIFF) output encoding
id3tag	Support ID3, ID3v2 tagging of audio files
mac	Enable support for Monkey's Audio files
normalize	Add support for normalizing audio file volume levels
replaygain	Support for Replay Gain metadata, for relative volume adjustment

abcm2ps

pango	Use the pango library to render fonts with non-latin characters

alsa-utils

bat	install basic audio tester (BAT) util
libsamplerate	install utils that use libsamplerate (e.g. alsaloop)
ncurses	install utils that use ncurses (e.g. alsamixer)

alsaplayer

id3tag	Enables ID3 tagging with id3tag library

amsynth

dssi	Enable support for DSSI Soft Synth Interface
lv2	Add support for Ladspa V2
nsm	Build support for Non Session Manager
vst	Build VST plug-in

apulse

sdk	Install PulseAudio headers and pkg-config files. Be aware apulse is not a full PulseAudio replacement by design and some functionality may be missing.

aqualung

ifp	Enable support for iRiver iFP portable audio players
lua	Enable support for programmable title formatting with dev-lang/lua
mac	Enable support for decoding Monkey's Audio files
podcast	Enable podcast support
systray	Enable system tray support

ardour

phonehome	contact ardour.org at startup for new announcements

ario

idle	Enable experimental support for MPD's idle command to reduce bandwidth and cpu usage, requires MPD 0.14

asunder

mac	Support for creation of Monkey's Audio files (APE)

audacity

audiocom	Enable integrated uploading to audio.com
id3tag	Enables ID3 tagging with id3tag library
lv2	Add support for Ladspa V2
mpg123	Use media-sound/mpg123-base instead of media-libs/libmad for MPEG decoding
portmixer	Enable the internal portmixer feature
sbsms	Enables sbsms library support for slower, more accurate pitch and tempo changing
twolame	Enables twolame support (MPEG Audio Layer 2 encoder)
vamp	Enables vamp plugins support (Audio analysing plugins)

audiotools

cue	Enable CUE sheet support
dvda	Enable DVD-Audio support
twolame	Enable twolame support (MPEG Audio Layer 2 encoder)

bluez-alsa

aptx	aptX (HD) over Bluetooth (many Android compatible headphones)
hcitop	Enable top-like monitoring tool for HCI
ldac	Enable support for AOSP media-libs/libldac dispatcher
liblc3	Enable LC3-SWB audio support for HFP
mpg123	Enable support for MPEG audio playback via media-sound/mpg123
msbc	Enable mSBC audio support for HFP
ofono	Enable oFono telephony support

cadence

a2jmidid	Enables support for legacy ALSA sequencer applications in JACK MIDI system

cantata

cdio	Use dev-libs/libcdio-paranoia for CD support (instead of cdparanoia)
http-server	Enable internal HTTP server to play non-MPD files
replaygain	Enable ReplayGain support, for relative volume adjustments
streaming	Enable playback of MPD HTTP streams using LibVLC (media-video/vlc)

cava

pipewire	Enable support for the media-video/pipewire backend
sndio	Enable support for the media-sound/sndio backend

clementine

box	Enable filesharing via Box.com
dropbox	Enable Dropbox support
googledrive	Enable Google Drive support
lastfm	Use liblastfm for fetching song info, scrobbling and radio streams
moodbar	Enable moodbar support
projectm	Build with ProjectM visualization
seafile	Enable support for seafile: a file sync service
skydrive	Enable Skydrive support
wiimote	Enable support for Wii remote

cmus

cdio	Use libcdio for CD support
discid	Enable reading the ID of the inserted CD
elogind	Enable MPRIS support via sys-auth/elogind
pidgin	Install support script for net-im/pidgin
sndio	Add support for media-sound/sndio
systemd	Enable MPRIS support via sys-apps/systemd
tremor	Use libivorbis from media-libs/tremor instead of media-libs/libvorbis

csound

beats	Build the beats score frontend
double-precision	Use double-precision floating point for audio samples
dssi	Build the DSSI opcodes
portmidi	Build the PortMIDI I/O module
samples	Install the HRTF datafiles for use with hrtfmove, hrtfmove2, hrtfstat, hrtfearly, and hrtfreverb
utils	Build stand-alone executables for utilities that can also be used via `csound -U`

darkice

twolame	Build with twolame support

deadbeef

converter	File format converter
cover	Support for cover art
hotkeys	Keyboard shortcuts support
lastfm	last.fm/AudioScrobbler protocol support
libretro	libretro resampling plugin
libsamplerate	Support the Secret Rabbit Code resampler
notify	Desktop notifications support
nullout	Dummy output driver
pipewire	Pipewire output plugin
sc68	Atari ST and Amiga music player
shellexec	Define custom shell commands that can be called on tracks
supereq	Enable equalizer

denemo

alsa	Enable alsa support through media-libs/alsa-lib
aubio	Enable media-libs/aubio support
jack	Enable jack support through virtual/jack
portaudio	Enable support for media-libs/portaudio
portmidi	Enable support for the media-libs/portmidi backend
rubberband	Enable support for media-libs/rubberband

dir2ogg

mac	Add support for decoding Monkey's Audio files
wma	Add support for wma files through mplayer

drumstick

fluidsynth	Enable support for media-sound/fluidsynth

easyeffects

calf	Enable use of media-plugins/calf for adding various FX
doc	Install packages needed to display built-in user documentation
mda-lv2	Enable use of media-plugins/mda-lv2 for the loudness FX
zamaudio	Enable use of media-plugins/zam-plugins for the maximizer FX

ecasound

lv2	Add support for Ladspa V2
oil	Use dev-libs/liboil for inner loop optimizations

elisa

mpris	Enable MPRIS support
vlc	Use media-video/vlc for output rather than dev-qt/qtmultimedia

fapg

xspf	Enable support for saving XSPF playlists.

fluidsynth

network	enable network support (requires BSD sockets)
pipewire	enable media-video/pipewire support

gimmix

cover	Enable cover art fetching
lyrics	Enable lyric fetching

guitarix

lv2	Build lv2 plugins
nsm	Build NSM (Non Session Manager) support
standalone	Build standalone application

hydrogen

archive	Use libarchive instead of libtar
portmidi	Add portmidi support

jack-audio-connection-kit

pam	Add basic realtime configuration via sys-auth/realtime-base

jack-example-tools

jack-net	Build jack_net_* example clients
jack-netsource	Build jack_netsource for configuring network sources
zalsa	Build the zalsa internal client using media-libs/zita-resampler

jack2

classic	Enable building of jackd
metadata	Enable metadata API
pam	Add basic realtime configuration via sys-auth/realtime-base
tools	Pull basic tools (e.g. jack_lsp/connect) from media-sound/jack-example-tools

kasts

vlc	Enable media-video/vlc backend

kid3

acoustid	Build acoustic fingerprinting plugin using media-libs/chromaprint
mpris	Enable support for MPRIS2 interface using dev-qt/qtdbus

klick

rubberband	Enable rubberband support

lame

frontend	Build and install the 'lame' executable frontend to lame libraries.
mp3rtp	Build the mp3-to-RTP streaming utility. **UNSUPPORTED**

liblc3

tools	Enable extra tools

linux-show-player

midi	Allow cues to send, or trigger on, MIDI messages
timecode	Support the sending of time code of running audio files over ArtNet, for instance to trigger cues in lighting-control software on lighting desks

linuxsampler

lv2	Add support for Ladspa V2
sf2	Add support for SoundFont 2 sound bank files

lmms

fluidsynth	Enables Fluidsynth MIDI software synthesis plugin.
libgig	Enables GIG player plugin.
soundio	Enables libsoundio support.
stk	Enables STK Mallet plugin.
vst	Enables the VeSTige plugin to run VST plugins through Wine.

mangler

espeak	Text to speech engine
g15	Logitech g15 lcd support

mixxx

hid	Enable HID controller support
keyfinder	Enable musical key detection support via media-libs/libkeyfinder
lv2	Add support for Ladspa V2 via media-libs/lilv
modplug	Add libmodplug support
qtkeychain	Enable Secure credential storage support via dev-libs/qtkeychain
shout	Enable broadcasting support via media-libs/libshout

moc

cache	Enable tags caching support
sndio	Enable support for the media-sound/sndio backend
tremor	Build vorbis support using an integer implementation of the vorbis library (media-libs/tremor)

mpd

cdio	Use libcdio for ISO9660 parsing support
chromaprint	Enable ChromaPrint / AcoustID support
cue	Enable CUE sheet support
curl	Support for web stream listening
eventfd	Use the eventfd function in MPD's event loop
faad	Use external faad library for AAC decoding
fifo	Support writing audio to a FIFO
fluidsynth	Enables Fluidsynth MIDI software synthesis (discouraged)
gme	Enables support for media-libs/game-music-emu for playing various video game music formats.
id3tag	Support for ID3 tags
inotify	Use the Linux kernel inotify subsystem to notice changes to mpd music library
io-uring	Enable support for io_uring
lame	Support for MP3 streaming via Icecast2
libmpdclient	Enable support for remote mpd databases
libsoxr	Enable the libsoxr resampler
mpg123	Enable support for mp3 decoding over media-sound/mpg123
network	Enables network streaming support
nfs	Enable support for the Network File System
openmpt	OpenMPT decoder plugin
pipe	Support writing audio to a pipe
pipewire	PipeWire support
qobuz	Build plugin to access qobuz
recorder	Enables output plugin for recording radio streams
signalfd	Use the signalfd function in MPD's event loop
snapcast	Snapcast audio plugin
sndio	Enable support for the media-sound/sndio backend
soundcloud	Build plugin to access soundcloud
systemd	Enable support for systemd socket activation
twolame	Support twolame MPEG-2 encoding
webdav	Enable using music from a WebDAV share
wildmidi	Enable MIDI support via wildmidi
yajl	Enable JSON parsing via dev-libs/yajl

mpfc

wav	Enable wav audio codec support

mpg123

int-quality	Use rounding instead of fast truncation for integer output, where possible

mpg123-base

int-quality	Use rounding instead of fast truncation for integer output, where possible

musescore

omr	Enable PDF import (OMR - optical music recognition)
osc	Enable OSC remote control protocol
portmidi	Enable support for building against media-libs/portmidi
sf3	Enable SoundFont 3 support using media-libs/libvorbis
sfz	Enable experimental SFZ sampler
video	Support exporting scores as videos using the command line
webengine	Use dev-qt/qtwebengine for embedded web browser

ncmpc

async-connect	Enable asynchronous connect
chat-screen	Enable the chat screen
help-screen	Enable the help screen
key-screen	Enable key editor screen
library-screen	Enable library screen
lyrics-screen	Enable lyrics screen
mouse	Enable curses getmouse support
outputs-screen	Enable the outputs screen
search-screen	Enable search screen
song-screen	Enable song viewer screen

ncmpcpp

clock	Enable clock screen
outputs	Enable outputs screen
visualizer	Enable visualizer screen with sound wave/frequency spectrum modes

ncspot

clipboard	Use the system clipboard to e.g. share a link
cover	Support displaying the album cover
mpris	Allow ncspot to be controlled via MPRIS API
ncurses	Use cursive/ncurses-backend instead of crossterm or pancurses
notify	Show what's playing via a notification

owntone

chromecast	build and install Chromecast support

patchage

jack-dbus	Use Jack via D-Bus instead of libjack

picard

discid	Enable reading the ID of the inserted CD
fingerprints	Enable calculation and lookup of AcoustID fingerprints

pithos

keybinder	Use keybinder to enable global key bindings

pms

regex	Enable regular expression searches

puddletag

acoustid	Use media-libs/chromaprint for acoustic fingerprinting
quodlibet	Enables support for editing media-sound/quodlibet databases

pulseaudio

daemon	Build the pulseaudio binary (not-needed for pipewire-pulse)
glib	Add support to dev-libs/glib-based mainloop for the libpulse client library, to allow using libpulse on glib-based programs. Build the GSettings PA module.
ofono-headset	Build with oFono HFP backend for bluez 5, requires net-misc/ofono.

pulseaudio-daemon

X	Build the X11 publish module to export PulseAudio information through X11 protocol for clients to make use. Don't enable this flag if you want to use a system wide instance. If unsure, enable this flag.
alsa-plugin	Request installing media-plugins/alsa-plugins with PulseAudio plugin enabled. This ensures that clients supporting ALSA only will use PulseAudio.
aptx	aptX (HD) over Bluetooth (many Android compatible headphones), requires media-plugins/gst-plugins-openaptx.
asyncns	Use libasyncns for asynchronous name resolution.
elogind	Use sys-auth/elogind for giving each session a PA client
equalizer	Enable the equalizer module (requires sci-libs/fftw and sys-apps/dbus).
fftw	Enable the virtual surround sink module (requires sci-libs/fftw).
gdbm	Use sys-libs/gdbm to store PulseAudio databases. Recommended for desktop usage. This flag causes the whole package to be licensed under GPL-2 or later.
glib	Build the GSettings PA module.
gstreamer	Build GStreamer-based RTP protocol module which supports more advanced RTP features like OPUS payload encoding.
ldac	LDAC over Bluetooth (primarily Sony headphones), requires media-plugins/gst-plugins-ldac.
ofono-headset	Build with optional oFono HFP backend for bluez 5, requires net-misc/ofono.
oss	Enable OSS sink/source (output/input). Deprecated, upstream does not support this on systems where other sink/source systems are available (i.e.: Linux). The padsp wrapper is now always build if the system supports OSS at all.
ssl	Use dev-libs/openssl to provide support for RAOP (AirPort) streaming.
system-wide	Allow preparation and installation of the system-wide init script for PulseAudio. Since this support is only supported for embedded situations, do not enable without reading the upstream instructions at https://www.freedesktop.org/wiki/Software/PulseAudio/Documentation/User/WhatIsWrongWithSystemWide/ .
systemd	Build with sys-apps/systemd support to replace standalone ConsoleKit.
webrtc-aec	Uses the webrtc.org AudioProcessing library for enhancing VoIP calls greatly in applications that support it by performing acoustic echo cancellation, analog gain control, noise suppression and other processing.

pulseeffects

bs2b	Enable use of media-libs/libbs2b for the crossfeed FX
calf	Enable use of media-plugins/calf for adding various FX
doc	Install packages needed to display built-in user documentation
rnnoise	Enable use of media-libs/rnnoise for the neural network-based noise-reduction FX
rubberband	Enable use of media-libs/rubberband for the pitch-shifting FX
webrtc	Enable use of media-plugins/gst-plugins-webrtc for various voice-enhancement FX
zamaudio	Enable use of media-plugins/zam-plugins for the maximizer FX

qmidiarp

lv2	Enables Ladspa V2 plugins.

qmmp

analyzer	Enable visual analyzer
archive	Enable archiving plugin via app-arch/libarchive.
bs2b	Enable Bauer stereophonic-to-binaural headphone filter
cover	Enable album cover support
crossfade	Enable crossfade effect when switching tracks
cue	enable CUE sheet parsing
dbus	Enable DBus notifiications and MPRIS support
enca	Detects the character encoding automatically
game	Enable Game music support
gnome	Enable Gnome hotkey support (requires Qt5DBus)
lyrics	Fetch track lyrics from the web
midi	Enable midi support using wildmidi library
notifier	Enable qmmps' notifier system
pipewire	Enable PipeWire output plugin
projectm	Enable projectm music visualization plugin
qsui	Enable QMMP simple UI
qtmedia	Enable playback via dev-qt/qtmultimedia
scrobbler	Enable audioscrobbler/last.fm support
shout	Enable shoutcast plug-in via media-libs/libshout.
sndfile	Enable wav playback support via media-libs/libsndfile
soxr	Use the SoX resampling library
stereo	Enable stereo effect
tray	Build tray icon
xmp	Enable module files renderer (modplug replacement)

qsampler

libgig	Enable libgig support for loading Gigasampler files and DLS (Downloadable Sounds) Level 1/2 files

qtractor

aubio	Enable media-libs/aubio support
dssi	Enable support for DSSI Soft Synth Interface
rubberband	Enable support for in-place audio clip pitch-shifting through the rubberband library

rhythmbox

daap	Build the local network music sharing plugin which uses the DAAP protocol using net-libs/libdmapsharing

scream

pcap	Support sniffing packets from network using net-libs/libpcap

shntool

alac	Add support for Apple Lossless Audio Codec files
mac	Add support for Monkey's Audio files
shorten	Add support for the shorten audio compressor

snapcast

client	Build and install Snapcast client component
server	Build and install Snapcast server component
tremor	Build with TREMOR version of vorbis

snd

notcurses	Terminal interface via dev-cpp/notcurses
s7	Enable the s7 extension language (a version of Scheme)

sonic-visualiser

id3tag	Enables ID3 tagging with id3tag library

sox

amr	Enables Adaptive Multi-Rate Audio support
id3tag	Enables ID3 tagging with id3tag library
sndio	Enable support for sndio
twolame	Enables twolame support (MPEG Audio Layer 2 encoder)

split2flac

enca	Try to guess the charset using enca
flake	Add support for Flake, alternative FLAC encoder
mac	Add support for Monkey's Audio files
replaygain	Support for Replay Gain metadata, for relative volume adjustment

spotify

local-playback	Allows playing local files with the Spotify client
pax-kernel	Triggers a paxmarking of the main Spotify binary
pulseaudio	Controls the dependency on pulseaudio or apulse

strawberry

moodbar	Enable moodbar support
soup	Allow streaming with media-plugins/gst-plugins-soup
vlc	Enable media-video/vlc backend

supercollider

ableton-link	Enable support for Ableton Link
emacs	Enable the SCEL user interface
gedit	Enable the SCED user interface
gpl3	Build GPL-3 licensed code (recommended)
server	Build with internal server
vim	Enable the SCVIM user interface
webengine	Enable the internal help system using QtWebengine

teamspeak-client

system-libcxx	Use sys-libs/libcxx instead of shipped libs.
system-quazip	Use dev-libs/quazip instead of shipped libs.

teamspeak-server

tsdns	Install TeamSpeaks own DNS service for handling multiple virtual servers.

upmpdcli

thirdparty	Enable streaming from Qobuz and Tidal external services

vimpc

boost	Use boost instead of C++11 libraries

vorbis-tools

kate	Adds support for Ogg Kate subtitles via libkate.
ogg123	Build ogg123 player, needs libao and curl

wildmidi

player	Install the wildmidi player
sndio	Enable support for the media-sound/sndio backend

xmms2

airplay	Support for airplay format
fluidsynth	Enable fluidsynth support (MIDI)
gme	Support for various game audio formats using media-libs/game-music-emu
ices	Icecast source output plugin
libvisual	Install xmms2-libvisual for use with the 'visualization' effect
mac	Support for Monkey's Audio (APE) format using media-sound/mac
mlib-update	Enable building of xmms2-mlib-updater client
server	Build xmms2 player daemon (otherwise only clients are built)
tremor	Support Vorbis using an alternate fixed-point decoder with media-libs/tremor
vocoder	Phase vocoder effect plugin
xml	Enable support for various XML based playlists and sources: RSS, XSPF

xwax

alsa	Adds support for ALSA audio input/output.
cdda	Sets runtime dependencies to support decoding audio from a compact disc.
fallback	Sets runtime dependencies to support decoding "other" audio files.
mp3	Sets runtime dependencies to support decoding MP3 audio.
oss	Adds support for OSS (open sound system) audio input/output.

yarock

mpv	Enable media-video/mpv backend
phonon	Enable media-libs/phonon backend
vlc	Enable media-video/vlc backend

yoshimi

lv2	Add support for Ladspa V2

zynaddsubfx

dssi	Enable support for DSSI Soft Synth Interface

media-tv

kodi

airplay	enable AirPlay support
bluetooth	Enable JSON-RPC over BT for remote control connected via bluetooth
bluray	Enable playback of Blu-ray filesystems
caps	Use sys-libs/libcap to bind to privileged ports as non-root
cec	Enable support for HDMI-CEC devices via libcec
eventclients	Install full set of Kodi python evenclients and evenclients examples
gbm	Use the Graphics Buffer Manager for EGL on KMS.
gles	Use simplified OpenGLES instead of full-scale OpenGL
libusb	Use virtual/libusb for usb device hotplug support. This flag should only be enabled if you're running a non-Linux kernel or you don't want to use udev.
lirc	Enable support for IR remote controls using app-misc/lirc
mariadb	Enable support store of media library metadata on local or remote MariaDB
mysql	Enable support store of media library metadata on local or remote MySQL
nfs	Enable NFS client support
optical	Enable Audio CD playback, optical disks detection and reading (CD-ROM, Video CD, and others), and ISO optical disk images direct reading. DVD disks may require additional 'udf' flag.
pipewire	Enable pipewire support
soc	Use additional media-video/ffmpeg patches for efficient playback on some SoCs (e.g. ARM, RISC-V)
system-ffmpeg	Use system ffmpeg instead of the bundled one
udev	Use udev rules to handle devices' permissions and hotplug support. Unless you know what you're doing do not disable this flag on Linux kernels. This is provided as an option for completeness.
udf	Enable UDF support. Required for playing blurays.
webserver	Enable internal webserver
xslt	Enable metadata XSLT scrapers support with dev-libs/libxslt

linuxtv-dvb-apps

alevt	Build videotext decoder

mythtv

alsa	Allows MythTV to directly output sound to ALSA devices
asi	Support for DVEO ASI recorder
autostart	Use a custom autostart configuration
cec	Allows control of CEC enabled TVs via HDMI
ceton	Ceton InfiniTV 4 a CableCARD-enabled tuner support
debug	Instructs Qt to use the 'debug' target
fftw	Support visualizations via sci-libs/fftw
hdhomerun	Silicondust USA Inc.network-attached tuner support
ieee1394	Firewire enabled Cable boxe support
jack	Allows MythTV to use JACK as your sound output device
java	BD-J support for Blu-ray discs
lcd	Enable use of app-misc/lcdproc data display
lirc	LIRC remote control device support
nvdec	Enable NVDEC (NVCUVID) hardware accelerated video decoding
perl	Build the perl bindings for MythTV
vbox	V@Box Communications network-attached tuner devices support
vpx	Enable VP8/VP9 support for media-libs/libvpx
wrapper	Use Ubuntu mythtfrontend wrapper
x265	Enable h265 encoding using x265
xmltv	Support media-tv/xmltv TV listing - not used by Schedules Direct]

tvheadend

ddci	Enable support for DDCI hardware
dvbcsa	Enable decryption of the DVB Common Scrambling Algorithm
hdhomerun	Enable support for the HDHomeRun device
imagecache	Enable support for image caching
iptv	Enable support for Internet Protocol TV
satip	Enable support for IP-based Satellite TV
timeshift	Enable TimeShift support
uriparser	Use dev-libs/uriparser
vpx	Enable transcoding with the VP8/VP9 video codecs
x264	Enable transcoding with the H.264 video codec
x265	Enable transcoding with the HEVC video codec
xmltv	Use media-tv/xmltv

xmltv

ar	Argentina tv listing grabber
ch-search	Grabber for Switzerland
eu-epgdata	include fanart URLs for some European countries.
eu-xmltvse	Grabbber for Europe [replaces eu-dotmedia and se-tvzon]
fi	Finland tv listing grabber (0.6.1 add ampparit telsu)
fi-sv	Grabber for Finland (Swedish)
fr	France tv listing grabber
huro	Hungarian tv listing grabber
is	Iceland tv listing grabber
it	Italy tv listing grabber (RUV)
it-dvb	Italy tv listing grabber
na-dd	North America tv listing grabber
na-dtv	North America Direct TV grabber
na-tvmedia	Grabber for North America (TVMedia)
pt-vodafone	Grabber for Portugal (Vodafone)
tr	Turkey (Digiturk) tv listing grabber
tv-check	enable GUI checking
tv-combiner	enable grabbers combiner
tv-pick-cgi	enable CGI support
uk-tvguide	UK and Ireland tv listing grabber using TV Guide website
zz-sdjson	Grabber for schedulesDirect.org SD-JSON service (many countries)
zz-sdjson-sqlite	Grabber for schedulesDirect.org SD-JSON service (sqlite DB)

media-video

aegisub

uchardet	Enable charset discovery via app-i18n/uchardet

amdgpu-pro-amf

pro	Pull media-libs/mesa as dependency
radv	Pull media-libs/amdgpu-pro-vulkan as dependency

aravis

fast-heartbeat	Enable faster heartbeat rate.
gstreamer	Build the GStreamer plugin.
packet-socket	Enable packet socket support.
viewer	Build the GTK+-based video viewer.

bluray_info

mpv	Build bluray_player, powered by media-video/mpv

droidcam

gtk	Build the dev-cpp/gtkmm:3.0 client.

dvd_info

libmpv	Build DVD player using libmpv

ffdiaporama

openclipart	Support openclipart database

ffmpeg

amf	Enables support for AMD's Advanced Media Framework (AMF)
amr	Enables Adaptive Multi-Rate Audio support
amrenc	Enables Adaptive Multi-Rate Audio encoding support with media-libs/vo-amrwbenc.
appkit	Enables Apple AppKit framework
bluray	Enable playback of Blu-ray filesystems
bs2b	Enables media-libs/libbs2b based Bauer stereo-to-binaural filter.
cdio	Enables audio CD grabbing with dev-libs/libcdio.
chromaprint	Enables audio fingerprinting support with media-libs/chromaprint.
chromium	Builds libffmpeg.so to enable media playback in Chromium-based browsers like Opera and Vivaldi.
codec2	Enables codec2 low bit rate speech codec support via media-libs/codec2.
cpudetection	Enables runtime CPU detection (useful for bindist, compatibility on other CPUs)
cuda	Enables CUDA-based acceleration. Mostly used for specific filters.
dav1d	Enables AV1 decoding via media-libs/dav1d.
fdk	Use external fdk-aac library for AAC encoding
flite	Adds a text-to-speech filter based on app-accessibility/flite.
frei0r	Enable frei0r wrapping in libavfilter
fribidi	Enables fribidi support in the drawtext filter.
gcrypt	Enables gcrypt support: Needed for rtmp(t)e support if openssl, librtmp or gmp is not used.
glslang	Use dev-util/glslang to compile GLSL
gme	Enables support for media-libs/game-music-emu for playing various video game music formats.
gpl	Build GPL code. Should be enabled unless you require LGPL binaries.
hardcoded-tables	Use pre-calculated tables rather than calculating them on the fly. It results in an increase of approximately 15% in the size of libavcodec, the main library impacted by this change. It enables savings in table generation time, done once at codec initialization, since by hardcoding the tables, they do not need to be computed at runtime. However, the savings are often negligible (~100k cycles is a typical number) especially when amortized over the entire encoding/decoding operation. Improvements are being made to the runtime initialization, and so over time, this option will have an impact on fewer and fewer codecs.
iec61883	Support for FireWire DV/HDV input device using media-libs/libiec61883.
kvazaar	Enables media-libs/kvazaar based HEVC encoder.
lcms	Enable ICC profile support via media-libs/lcms.
libaom	Enables media-libs/libaom based AV1 codec support.
libaribb24	Enables ARIB text and caption decoding via media-libs/aribb24.
libdrm	Enables x11-libs/libdrm support for better screen grabbing and hardware accelerated codecs.
libdvdnav	Uses media-libs/libdvdnav to enable DVD demuxing
libdvdread	Uses media-libs/libdvdread to enable DVD demuxing
libilbc	Enables iLBC de/encoding via media-libs/libilbc.
liblc3	Enables LC3 de/encoding via media-sound/liblc3.
libplacebo	Adds flexible GPU-accelerated processing filter based on media-libs/libplacebo.
librtmp	Enables Real Time Messaging Protocol using librtmp (media-video/rtmpdump) in addition to FFmpeg's native implementation.
libsoxr	Enables audio resampling through media-libs/soxr.
libtesseract	Enables the OCR filter via app-text/tesseract.
libv4l	Uses media-libs/libv4l for video4linux instead of direct calls. Adds support for more devices via the userspace library.
libxml2	Uses dev-libs/libxml2 to enable dash demuxing support.
lv2	Enables lv2 audio filter wrapper.
mipsdspr1	Enables MIPS DSP ASE R1 optimizations.
mipsdspr2	Enables MIPS DSP ASE R2 optimizations.
mipsfpu	Enables floating point MIPS optimizations.
mmal	Enables Multi-Media Abstraction Layer (MMAL) decoding support: Available e.g. on the Raspberry Pi.
network	Enables network streaming support
openh264	Enables H.264 encoding suppoprt via media-libs/openh264.
openssl	Enables dev-libs/openssl support. Adds support for encrypted network protocols (TLS/HTTPS).
pic	Force shared libraries to be built as PIC (this is slower)
postproc	Build and install libpostproc.
qrcode	Enables QR encode generation via media-gfx/qrencode
qsv	Enable Intel Quick Sync Video via media-libs/intel-mediasdk (ffmpeg versions older than, and including, 5.1) or media-libs/libvpl (ffmpeg version newer than 5.1).
quirc	Enables QR decoding via media-libs/quirc
rav1e	Enables AV1 encoding support via media-video/rav1e.
rubberband	Adds time-stretching and pitch-shifting audio filter based on media-libs/rubberband.
shaderc	Use media-libs/shaderc to compile GLSL
snappy	Enable app-arch/snappy support. Required for e.g. Vidvox Hap encoder.
sndio	Enable support for the media-sound/sndio backend
soc	Apply additional patches for efficient playback on some SoCs (e.g. ARM, RISC-V).
srt	Enable support for Secure Reliable Transport (SRT) via net-libs/srt
ssh	Enable SSH/sftp support via net-libs/libssh.
svt-av1	Enables AV1 encoding support via media-libs/svt-av1.
truetype	Enables drawtext filter via media-libs/freetype and media-libs/harfbuzz.
twolame	Enables MP2 encoding via media-sound/twolame as an alternative to the internal encoder.
vidstab	Enables video stabilization filter using vid.stab library (media-libs/vidstab).
vmaf	Enables Netflix's perceptual video quality assessment filter using the library (media-libs/libvmaf).
vpx	Enables VP8 and VP9 codec support using libvpx: Decoding does not require this to be enabled but libvpx can also be used for decoding; encoding requires this useflag to be enabled though.
x265	Enables HEVC encoding with media-libs/x265.
zeromq	Enables net-libs/zeromq support with the zmq/azmq filters.
zimg	Enables media-libs/zimg based scale filter.
zvbi	Enables media-libs/zvbi based teletext decoder.

ffmpeg-chromium

cpudetection	Enables runtime CPU detection (useful for bindist, compatibility on other CPUs)
gpl	Build GPL code. Should be enabled unless you require LGPL binaries.

guvcview

qt5	Build with Qt5 interface instead Gtk+

handbrake

fdk	Support for encoding AAC using media-libs/fdk-aac.
gstreamer	Support for the streaming media framework from media-libs/gstreamer.
gtk	Install the GTK UI, ghb.
numa	Adds support for x265's NUMA capabilities.
x265	Support for encoding h265 using media-libs/x265.

libva-utils

examples	Build and install decode, encode, videoprocess and other VA-API examples.
putsurface	Build and install putsurface tool.
vainfo	Build and install vainfo tool.

makemkv

java	Handle additional Blu-ray protection mechanisms involving Java

mjpegtools

sdlgfx	Enables y4mhist to display a graphical histogram

mjpg-streamer

http-management	Enable experimental HTTP management option
input-control	Plugin giving ability to control camera movement (only specific cameras)
input-file	Plugin that watches given directory and send it's content
input-http	Plugin that takes http-input
input-ptp2	Plugin that sends video stream from PTP2 compatible camera
input-raspicam	Raspberry Pi camera support via the input_raspicam plugin
input-testpicture	Plugin for sending compiled in, test pictures
input-uvc	Plugin that sends video stream from UVC compatible camera
output-autofocus	Auto focusing plugin
output-file	Plugin that saves received content under given location
output-http	Small HTTP server plugin which sends WWW directory content and streams image content
output-rtsp	Plugin which provides a mechanism to take snapshots with a trigger from a UDP packet
output-udp	Plugin receiving content over UDP and storing to a directory
output-viewer	Plugin which allows to see output with viewer
output-zmqserver	Plugin which provides zmqserver processing
www	Installs WWW content
wxp-compat	Enable camera WXP compatible format

motion

mariadb	Add mariadb database support
mmal	Enables Multi-Media Abstraction Layer (MMAL) decoding support: Available e.g. on the Raspberry Pi.

motiontrack

multiprocess	Enables multi-process support (SMP/cluster) for motiontrack programs

mplayer

bl	Blinkenlights video output
bluray	Enable playback of Blu-ray filesystems
bs2b	Enable Bauer stereophonic-to-binaural headphone filter
cdio	Use libcdio for CD support (instead of cdparanoia)
cdparanoia	Enable cdparanoia (audio CD ripper) support
cpudetection	Enables runtime CPU detection (useful for binpkgs, compatibility on other CPUs)
dvdnav	Use forked libdvdnav, navigate menus in GUIs
enca	Enables support for charset discovery and conversion
faac	Use external faac library for AAC encoding
faad	Use external faad library for AAC decoding
libmpeg2	Build support for mpeg2 over media-libs/libmpeg2 rather than using ffmpeg.
live	Enables live.com streaming media support
md5sum	Enables md5sum video output
mng	MNG input support
network	Enables network streaming support
osdmenu	Enables support for on-screen display (OSD) menus
pnm	Add PNM video output option, to create PPM/PGM/PGMYUV images
pvr	Enable Video4Linux2 MPEG PVR
radio	Enable V4L2 radio interface and support
rar	Enable Unique RAR File Library
rtc	Enables usage of the linux real time clock. The alternative is software emulation of rtc
rtmp	Enables RTMPDump Streaming Media support
shm	Enable support for shm
tga	Enables Targa video output
toolame	Enable toolame MPEG-2 encoding
tremor	Enable internal support for Vorbis
twolame	Enable twolame MPEG-2 encoding
vcd	Enables VCD support
vidix	Support for vidix video output
yuv4mpeg	Enables yuv4mpeg video output
zoran	Enables ZR360[56]7/ZR36060 video output

mpv

archive	Enable support for various archive formats via app-arch/libarchive
bluray	Enable playback of Blu-ray filesystems
cli	Enable the command-line player
drm	Enable Kernel Mode Setting / Direct Rendering Manager based video outputs
gamepad	Enable gamepad input support
libmpv	Enable the shared library and headers (used by frontends / plugins)
lua	Enable Lua scripting, OSC (On Screen Controller) GUI, and net-misc/yt-dlp support
opengl	Enable support for OpenGL-based video backends (Note: deprecated for X11, USE=egl provides the newer support for -gpu-api=opengl)
pipewire	Enable sound support via native PipeWire backend
rubberband	Enable high quality pitch correction via media-libs/rubberband
sdl	Enable media-libs/libsdl2 based video and audio outputs (Note: these outputs exist for compatibility reasons only, avoid if possible)
sixel	Enable support for the sixel video backend using media-libs/libsixel
sndio	Enable sound support via media-sound/sndio
soc	Use additional media-video/ffmpeg patches for efficient playback on some SoCs (e.g. ARM, RISC-V)
tools	Install extra tools: mpv_identify.sh, mpv_idet.sh, and umpv
uchardet	Enable subtitles charset discovery via app-i18n/uchardet
zimg	Enable libzimg support (for vf_fingerprint)

noad

libmpeg2	Build support for mpeg2 through media-libs/libmpeg2 rather than using media-video/ffmpeg

obs-studio

browser	Enable browser source support via (precompiled) CEF.
decklink	Build the Decklink plugin.
fdk	Build with LibFDK AAC support.
mpegts	Enable native SRT/RIST mpegts output.
pipewire	Build with PipeWire support.
python	Build with scripting support for Python 3.
qsv	Build with Intel Quick Sync Video support.
sndio	Build with sndio support.
speex	Build with Speex noise suppression filter support.
test-input	Build and install input sources used for testing.
vlc	Build with VLC media source support.
websocket	Build with WebSocket API support.

peek

keybinder	Enable support for global hotkeys using dev-libs/keybinder

pipewire

X	Enable audible bell for X11
echo-cancel	Enable WebRTC-based echo canceller via media-libs/webrtc-audio-processing
extra	Build pw-cat/pw-play/pw-record
flatpak	Enable Flatpak support
gsettings	Use gsettings (dev-libs/glib) to read/save used modules (useful for e.g. media-sound/paprefs
jack-client	Install a plugin for running PipeWire as a JACK client
jack-sdk	Use PipeWire as JACK replacement
liblc3	Allow loading LC3 plugins via media-sound/liblc3
lv2	Allow loading LV2 plugins via media-libs/lv2
modemmanager	Combined with USE=bluetooth, allows PipeWire to perform telephony on mobile devices.
pipewire-alsa	Replace PulseAudio's ALSA plugin with PipeWire's plugin
roc	Enable roc support for real-time audio streaming over the network, using media-libs/roc-toolkit. See https://gitlab.freedesktop.org/pipewire/pipewire/-/wikis/Network#roc
sound-server	Provide sound server using ALSA and bluetooth devices
ssl	Enable raop-sink support (needs dev-libs/openssl)
system-service	Install systemd unit files for running as a system service. Not recommended.

qmplay2

audiofilters	Build with AudioFilters module
avdevice	Build FFmpeg module with libavdevice suport
cdio	Build with AudioCD module
cuvid	Build with CUVID module
extensions	Build with Extensions module and enable other plugins
gme	Build Chiptune with GME support
inputs	Build with Inputs module
libass	Build with SSA/ASS subtitles rendering support
notifications	Build additional notifications module
pipewire	Build with PipeWire support
shaders	Compile Vulkan shaders using media-libs/shaderc
videofilters	Build with VideoFilters module
visualizations	Build with Visualizations module

rav1e

capi	Build the C-API library and header file

rtmpdump

gnutls	Use GnuTLS instead of OpenSSL for Cryptography
ssl	Enable Cryptographic features
tools	Enable installation of various binary tools in addition to librtmp library

simplescreenrecorder

asm	Enable x86 assembly optimisation.
vpx	Enable VP8 codec support via media-libs/libvpx.

totem

python	Build dev-lang/python using plugins (dbusservice for notifications and MPRIS control, interactive python console and opensubtitles lookup)

vdr

alternatechannel	Use alternate channel on record
bidi	fribidi support, for languages, written from right to left
demoplugins	Install demo and example plugins coming with vanilla vdr
graphtft	support for vdr-graphtft plugin up from version 0.1.7
html	Install HTML documentation
keyboard	enable keyboard support as remote device
mainmenuhooks	Allows to replace main menu entries by some special plugins (like epgsearch, extrecmenu, ...)
menuorg	Enables support for the media-plugins/vdr-menuorg
menuselection	adds support for menu hotkeys of double digits
naludump	Removes NALU fill data from h.264-Streams of TS files
permashift	permanent timeshift by recording live TV into RAM, need plugin media-plugins/vdr-permashift
pinplugin	Support for media-plugins/vdr-pin
resumereset	rreset resume of EOF
ttxtsubs	support for media-plugins/vdr-ttxtsubs
verbose	enable full output on compile

vidify

dbus	Support local MPRIS players
mpv	Use python-mpv as backend for vidify
vlc	Use python-vlc as backend for vidify
zeroconf	Use an external network player

vlc

X	Enable support for e.g. fullscreen mode via X and the X C-language binding. It does not build a graphical interface
aom	Enable AV1 encoding/decoding support using media-libs/libaom
archive	Enable support for libarchive stream extractor
aribsub	Enable support for decoding ARIB STD-B24 subtitles
bluray	Enable libbluray for Blu-ray disc support
chromaprint	Enable libchromaprint for Chromaprint based audio fingerprinter support
chromecast	Enable experimental support for Google Chromecast
dav1d	Enable support for media-libs/dav1d AV1 decoder
dc1394	Enable IIDC cameras support
directx	Enable Win32 DirectX, D3D11va and DxVA2 support
dvbpsi	Enable support for Mpeg-TS files (.ts, .m2ts, .mts) via media-libs/libdvbpsi
encode	Enable streaming-output support and videolan manager to control multiple streams from within one instance
faad	Enable AAC audio decoding library support via media-libs/faad2
fdk	Enable the Fraunhofer AAC codec library
fluidsynth	Enable Fluidsynth MIDI software synthesis (with external sound fonts)
gcrypt	Enable cryptography support via libgcrypt
gme	Enable support for media-libs/game-music-emu for playing various video game music formats
gstreamer	Enable GStreamer based decoding support (currently supports only video decoding)
kate	Adds support for Ogg Kate subtitles via libkate
kms	Enable kernel mode setting video output plugin via x11-libs/libdrm
libplacebo	Enable support for GPU accelerated video rendering with media-libs/libplacebo
libtar	Uses libtar instead of the built-in tar reader for reading custom skins
libtiger	Enable Ogg Kate subtitles rendering using libtiger
linsys	Enable support for Linux Linear Systems Ltd. SDI and HD-SDI input cards
live	Enable live555 streaming media support (client support for rtsp)
loudness	Enable loudness normalisation according to the EBU R128 standard using media-libs/libebur128
lua	Enable Lua scripting support, needed for including support for Jamendo (online music platform) and similar things
macosx-notifications	Enable Mac OS X notifications module (formerly growl)
matroska	Enable matroska support using reference libraries (fallback on other existing matroska support if disabled, i.e., matroska enabled FFmpeg)
mpeg	Add libmpeg2 support for mpeg-1 and mpeg-2 video streams
nfs	Enable support for nfs protocol via net-fs/libnfs
omxil	Enable OpenMAX Integration Layer codec module
optimisememory	Enable optimisation for memory rather than performance
projectm	Enable the projectM visualization plugin
run-as-root	Allows vlc to start for root. Don't enable this unless you have a very specific (e.g. embedded) need for it!
sdl-image	Enable sdl image video decoder (depends on sdl)
sftp	Enable libssh2 to support SFTP file transfer
shout	Enable libshout output
skins	Enable support for the skins2 interface
soxr	Enable SoX Resampler support via media-libs/soxr
srt	Enable support for Secure Reliable Transport (SRT) via net-libs/srt
tremor	Enable tremor, a fixed-point version of the Ogg Vorbis decoder
twolame	Enable twolame support (MPEG Audio Layer 2 encoder)
upnp	Enable support for the Intel SDK stack based UPnP discovery module instead of CyberLink
vpx	Enable the decoder(s) from the WebM VP8 / VP9 Codec SDK
x265	Support X265 Encoder
zeroconf	Enable support for zero-configuration networking via avahi
zvbi	Enable support for teletext subtitles via the zvbi library

webcamoid

headers	Install development headers
libuvc	Build with libuvc support
qtaudio	Enable audio capture/play via dev-qt/qtmultimedia
qtcamera	Enable video capture/play via dev-qt/qtmultimedia
v4lutils	Build with V4L-utils support
videoeffects	Build video effects

wireplumber

system-service	Install systemd unit files for running as a system service. Not recommended.

x264-encoder

avs	enable AvxSynth support in the AviSynth input module
ffmpegsource	Enable ffmpegsource aka ffms support, disables lavf
interlaced	Enable interlaced encoding support, this can decrease encoding speed by up to 2%

xine-ui

vdr	Enables Video Disk Recorder support

net-analyzer

2ping

server	Install the server init scripts.

argus-clients

ft	Enable support for flow packets through net-analyzer/flow-tools

barnyard

sguil	Enable sguil (The Analyst Console for Network Security Monitoring) support

barnyard2

gre	Enable GRE support
mpls	Enable support for mpls networks
sguil	Enable sguil (The Analyst Console for Network Security Monitoring) support

bwm-ng

csv	Enable csv output
html	Enable html output

cacti

doc	install html documentation

echoping

http	enable support for http protocol.
icp	enable support for ICP (used to monitor proxies).
priority	enable socket priority support.
smtp	enable support for SMTP protocol.
tos	enable support for TOS (TYpe Of Service).

ettercap

plugins	Install ettercap plugins (et_*.so)

flowgrind

pcap	Enable packet capturing support using net-libs/libpcap

fprobe

messages	enable console messages

goaccess

geoipv2	Enable support for GeoIP2 through dev-libs/libmaxminddb
getline	Use GNU getline() to parse full line requests

gr-fosphor

glfw	enable GLFW based interface

greenbone-feed-sync

cron	Adds file to enable daily cron job to update Greenbone Community Feed's data"

gvm

cli	Command Line Interface for OpenVAS Scanner
gsa	Greenbone Security Assistant (WebUI)
ospd	Enable support for scanner wrappers

hexinject

experimental	Install experimental packets.tcl
tools	Install hex2raw and prettypacket tools

httping

tfo	Enable support for TCP Fast Open

hydra

gcrypt	Enable radmin2 support through dev-libs/libgcrypt
libssh	Enable SSH support through net-libs/libssh
mongodb	MongoDB support through dev-libs/mongo-c-driver

icinga2

console	Adds support for line-editing in the console
jumbo-build	Combine source files to speed up build process, requires more memory
mail	Allows for mailing of alerts
mariadb	Enable support for the mariadb database backend
nano-syntax	Adds support for syntax used in the nano editor
plugins	Adds support for nagios plugins

ipsumdump

nanotimestamp	Enable timestamps with nano-second resolution

linkchecker

sqlite	Mozilla Bookmark parsing

monitoring-plugins

dns	Install net-dns/bind-tools required for monitoring DNS servers. Disabling the flag does not remove any plugins.
fping	Install net-analyzer/fping required for fancy ping monitoring. Disabling the flag does not remove any plugins.
game	Install games-util/qstat required for monitoring FPS servers. Disabling the flag does not remove any plugins.
ipv6	Enable ipv6 checks.
snmp	Install dev-perl/Net-SNMP and net-analyzer/net-snmp required for monitoring SNMP values. Disabling the flag does not remove any plugins.
ssh	Install net-misc/openssh required for monitoring SSH servers. Disabling the flag does not remove any plugins.

mtr

ipinfo	Disable support for IP address lookups
jansson	Enable JSON output support through dev-libs/jansson

munin

asterisk	Install the packages required for monitoring Asterisk. Disabling the flag does not remove any plugin files.
cgi	Install the CGI-compatible scripts for on-the-fly generation of web pages and graphs. This is only meaningful if the minimal USE flag is disabled.
dhcpd	Install dev-perl/Net-IP, dev-perl/HTTP-Date and net-misc/dhcp to monitor DHCP lease usage. This only works if the server is on the same system as the node, so the server is also brought in. Disabling the flag does not remove any plugin file.
doc	Build and install a local copy of the HTML documentation for the whole software. This requires dev-python/sphinx to process the documentation sources.
http	Install dev-perl/libwww-perl required for monitoring HTTP-based services such as Apache and nginx. Disabling the flag does not remove any plugin file.
ipmi	Install sys-apps/ipmitool required for monitoring IPMI sensors. Disabling the flag does not remove any plugin file.
ipv6	Add support for IPv6 in munin-node. IPv6 support for the master is always enabled, but the node requires a newer version of dev-perl/Net-Server, capable of listening to IPv6 sockets.
irc	Install the packages required for monitoring IRC. Disabling the flag does not remove any plugin files.
java	Build the Java-based plugins to monitor JMX-compatible applications. Disabling the flag removes the jmx monitoring plugins.
memcached	Install the packages required for memcached monitoring. Disabling the flag does not remove any plugin files.
minimal	Only install munin-node and its plugins. This excludes the scripts to generate the web pages and the graphs.
mysql	Install the packages required for monitoring MySQL. Disabling the flag does not remove any plugin files.
postgres	Install the packages required for monitoring PostgreSQL. Disabling the flag does not remove any plugin files.
syslog	Configure the node by default to log on syslog. This requires the presence of virtual/perl-Sys-Syslog. As of version 2.0.2, the master scripts only log to file, and not to syslog.

nagios-core

classicui	use the classic web theme
lighttpd	install www-servers/lighttpd config
web	enable web interface

nagios-plugin-check_raid

3ware	Support 3ware RAID controllers
aacraid	Support Adaptec AAC-RAID controllers
dmraid	Support Device-Mapper RAID
hpa	Support HP Array controllers
hpsa	Support HP SmartArray (CCISS) controllers
megaraid-sas	Support LSI MegaRAID SAS controllers
mpt	Support LSI MPT Fusion controllers
mpt-sas2	Support LSI SAS-2 controllers

nagios-plugins

ipv6	Enable ipv6 checks.
nagios-dns	Install net-dns/bind-tools required for monitoring DNS servers. Disabling the flag does not remove any plugin file.
nagios-game	Install games-util/qstat required for monitoring FPS servers. Disabling the flag does not remove any plugin file.
nagios-ping	Install net-analyzer/fping required for fancy ping monitoring. Disabling the flag does not remove any plugin file.
snmp	Install dev-perl/Net-SNMP required for monitoring SNMP values. Disabling the flag does not remove any plugin file.
ssh	Install net-misc/openssh required for monitoring SSH servers. Disabling the flag does not remove any plugin file.

nagios-plugins-linux-madrisan

curl	Build check_container which requires net-misc/curl
varlink	Build check_podman which requires dev-libs/libvarlink

net-snmp

elf	Enable the use of elf utils to check uptime on some systems
kmem	Enable usage of /dev/kmem
mfd-rewrites	Use MFD rewrites of mib modules where available
netlink	Use dev-libs/libnl to fetch TCP statistics instead of using /proc/net/tcp (Linux only).
pcap	Install snmppcap which reads from PCAP files and writes to the SNMP transport
pci	Use libpci (from sys-apps/pciutils) to look up network interface description. This feature is only available on Linux.
pcre	Add support for Perl Compatible Regular Expressions in process table filtering.
rpm	Enable monitoring of app-arch/rpm. This flag requires the bzip2 and zlib flags to be enabled as well.
smux	Enable support for the legacy smux protocol (superseded by agentx)
ucd-compat	Build UCD compatibility library. Increases significantly the install size.

netdata

aclk	Enable Agent-Cloud Link (ACLK) for securely connecting a Netdata Agent to your web browser through Netdata Cloud
bpf	Enable the extended Berkeley Packet Filter (eBPF) collector to monitor kernel-level metrics about applications with per-second granularity
cloud	Enable Netdata Cloud support
dbengine	Enable the Netdata database engine
ipmi	Install sys-apps/ipmitool required for monitoring IPMI sensors.
mongodb	Enable support for the mongodb backend
nfacct	Enable the nfacct plugin
nodejs	Enable use of nodejs (which some plugins use)
prometheus	Enable support for the Prometheus remote write backend
tor	Enable monitoring of tor
xen	Enable monitoring of xen

netperf

demo	Emit interim results during the run. May affect results

nfdump

ftconv	Build the flow-tools to nfdump converter
jnat	Build nfudmp to support JunOS NAT event logging
nfpcapd	Build nfpcapd collector to create netflow data from precollected pcap traffic
nfprofile	Build nfprofile used by NfSen
nftrack	Build nfprofile used by PortTracker
nsel	Build nfudmp to support NSEL/NEL event data
readpcap	Build nfcapd collector to read from pcap file instead ofnetwork data
sflow	Build sflow collector sfcpad

nmap

libssh2	Enable SSH support through net-libs/libssh2
ncat	Install the ncat utility
ndiff	Install the ndiff utility
nping	Install the nping utility
nse	Include support for the Nmap Scripting Engine (NSE)
symlink	Install symlink to nc
zenmap	Install the GTK+ based nmap GUI, zenmap

nrpe

command-args	Build support for specifying the command-line arguments from the Nagios/Icinga master. Make sure you understand the implications of this flag as it can be a security risk.

nsca

crypt	Build support for crypted communication with nsca, through dev-libs/libmcrypt. It's recommended not to disable this flag unless all the communication will be handled in an absolutely safe environment.
minimal	Only build and install the send_nsca command and not the daemon. This allows a very minimal install with no overhead when setting up a node.

openvas-scanner

snmp	Build againts net-analyzer/net-snmp for "improved SNMP support"

ospd-openvas

notus	Set systemd service file to use notus-scanner

ossec-hids

agent	Build "agent" installation target (see package description)
hybrid	Build "hybrid" installation target
local	Build "local" installation target
server	Build "server" installation target

pinger

gtk2	Install the gtkpinger GUI utility based on x11-libs/gtk+:2
gtk3	Install the gtkpinger GUI utility based on x11-libs/gtk+:3

pmacct

bgp-bins	Link BGP daemon binaries
bmp-bins	Link BMP daemon binaries
geoipv2	Enable support for GeoIP2 through dev-libs/libmaxminddb
jansson	Enable support for JSON through dev-libs/jansson
kafka	Enable support for Apache Kafka through dev-libs/librdkafka
l2	Enable Layer-2 features and support
ndpi	Enable support for nDPI through net-libs/nDPI
nflog	Enable support for NFLOG through uacctd
rabbitmq	Enable support for RabbitMQ through net-libs/rabbitmq-c
st-bins	Link Streaming Telemetry daemon binaries
traffic-bins	Link IPv4/IPv6 traffic accounting binaries
zmq	Enable support for ZeroMQ through net-libs/zeromq

pnp4nagios

icinga	Build against net-analyzer/icinga2 instead of net-analyzer/nagios-core
nagios	Build against net-analyzer/nagios-core (the default)

rrdcollect

exec	Enable exec:/// support
librrd	Use the librrd library from net-analyzer/rrdtool

rrdtool

graph	Enable support for graphing functions
rados	Enable support for librados from sys-cluster/ceph
rrdcached	Build support for write-caching daemon
rrdcgi	Build rrdcgi support

rustscan

nmap	Installs net-analyzer/nmap

sancp

sguil	Enable sguil (The Analyst Console for Network Security Monitoring) support

sarg

doublecheck	Make sarg double check the data it manipulates and output a warning if an error is found
gd	Enable support for graphs in reports through media-libs/gd
glob	Disable to ignore wildcards in file names
pcre	Enable support for regular expressions in the hostalias file through dev-libs/libpcre

scanlogd

nids	Use net-libs/libnids for packet capturing
pcap	Use net-libs/libpcap for packet capturing

sngrep

eep	Enable EEP packet send/receive support
gnutls	Use net-libs/gnutls to parse captured TLS packets

snort

active-response	Enables support for automatically sending TCP resets and ICMP unreachable messages to terminate connections. Used with inline deployments.
control-socket	Enables Snort's control socket.
file-inspect	Enables extended file inspection capabilities.
flexresp3	Enables support for new flexable response preprocessor for enabling connection tearing for inline deployments. Replaces flexresp and flexresp2.
gre	Enable support for inspecting and processing Generic Routing Encapsulation (GRE) packet headers. Only needed if you are monitoring GRE tunnels.
high-availability	Enables high-availability state sharing.
inline-init-failopen	Enables support to allow traffic to pass (fail-open) through inline deployments while snort is starting and not ready to begin inspecting traffic. If this option is not enabled, network traffic will not pass (fail-closed) until snort has fully started and is ready to perform packet inspection.
large-pcap-64bit	Allows Snort to read pcap files that are larger than 2 GB. ONLY VALID FOR 64bit SYSTEMS!
libtirpc	Build against net-libs/libtirpc for RPC support
linux-smp-stats	Enable accurate statistics reporting through /proc on systems with multiple processors.
non-ether-decoders	Enable decoding of non-ethernet protocols such as TokenRing, FDDI, IPX, etc.
open-appid	Enable OpenAppID, an open, application-focused detection language and processing module for Snort that enables users to create, share, and implement application detection. Requires dev-lang/luajit.
perfprofiling	Enables support for preprocessor and rule performance profiling using the perfmonitor preprocessor.
ppm	Enables support for setting per rule or per packet latency limits. Helps protect against introducing network latency with inline deployments.
react	Enables support for the react rule keyword. Supports interception, termination, and redirection of HTTP connections.
reload-error-restart	Enables support for completely restarting snort if an error is detected during a reload.
shared-rep	Enables the use of shared memory for the Reputation Preprocessor (Only available on Linux systems)
side-channel	Enables Snort's side channel.
sourcefire	Enables Sourcefire specific build options, which include --enable-perfprofiling and --enable-ppm.

suricata

af-packet	Enable AF_PACKET support
af-xdp	Enable AF_XDP support
bpf	Enable support for eBPF (as well as XDP if supported by the kernel and the NIC driver) for low-level, high-speed packet processing
control-socket	Enable unix socket
detection	Enable detection modules
hyperscan	Enable high-performance regex matching with Hyperscan
lz4	Enable support for compressed pcap logging using the LZ4 algorithm
nflog	Enable libnetfilter_log support
nfqueue	Enable NFQUEUE support for inline IDP
redis	Enable Redis support

symon

perl	Enables a generic perl symux client
symon	Enables the system monitor. Offers no functionality but monitoring and forwarding of measured data
symux	Enables the multiplexer which stores incoming symon streams on disk in RRD (net-analyzer/rrdtool) files

tcpdump

drop-root	Drop privileges to pcap:pcap when run as root
smi	Build with net-libs/libsmi to load MIBs on the fly to decode SNMP packets

tcpreplay

pcapnav	Enable if you want the jump to byte offset feature via net-libs/libpcapnav
tcpdump	Use net-analyzer/tcpdump for packet decoding feature

testssl

bundled-openssl	Install precompiled versions of OpenSSL for greater testing coverage

tracebox

curl	Build the curl component for uploading capture files using net-misc/curl
sniffer	Build the sniffer component using net-libs/libnetfilter_queue

wireshark

androiddump	Install androiddump, an extcap interface to capture from Android devices
bcg729	Use media-libs/bcg729 for G.729 codec support in RTP Player
capinfos	Install capinfos, to print information about capture files
captype	Install captype, to print the file types of capture files
ciscodump	Install ciscodump, extcap interface to capture from a remote Cisco router
dftest	Install dftest, to display filter byte-code, for debugging dfilter routines
dpauxmon	Install dpauxmon, an external capture interface (extcap) that captures DisplayPort AUX channel data from linux kernel drivers
dumpcap	Install dumpcap, to dump network traffic from inside wireshark
editcap	Install editcap, to edit and/or translate the format of capture files
http3	Install net-libs/nghttp3 for enhanced HTTP3 analysis
ilbc	Build with iLBC support in RTP Player using media-libs/libilbc
libxml2	Use dev-libs/libxml2 for handling XML configuration in dissectors
maxminddb	Use dev-libs/libmaxminddb for IP address geolocation
mergecap	Install mergecap, to merge two or more capture files into one
minizip	Build with zip file compression support
netlink	Use dev-libs/libnl
pcap	Use net-libs/libpcap for network packet capturing (build dumpcap, rawshark)
plugins	Install plugins
qt6	Build with Qt6 support instead of the default Qt5 for GUI support
randpkt	Install randpkt, a utility for creating pcap trace files full of random packets
randpktdump	Install randpktdump, an extcap interface to provide access to the random packet generator (randpkt)
reordercap	Install reordercap, to reorder input file by timestamp into output file
sbc	Use media-libs/sbc for playing back SBC encoded packets
sdjournal	Install sdjournal, an extcap that captures systemd journal entries
sharkd	Install sharkd, the daemon variant of wireshark
smi	Use net-libs/libsmi to resolve numeric OIDs into human readable format
spandsp	Use media-libs/spandsp for for G.722 and G.726 codec support in the RTP Player
sshdump	Install sshdump, an extcap interface to capture from a remote host through SSH
text2pcap	Install text2pcap, to generate a capture file from an ASCII hexdump of packets
tfshark	Install tfshark, a terminal-based version of the FileShark capability
tshark	Install tshark, to dump and analyzer network traffic from the command line
udpdump	Install udpdump, to get packets exported from a source (like a network device or a GSMTAP producer) that are dumped to a pcap file
wifi	Install wifidump, to dump and analyse 802.11 traffic

zabbix

agent	Enable zabbix agent (for to-be-monitored machines)
agent2	Enable go-based zabbix agent 2 (for to-be-monitored machines)
frontend	Enable zabbix web frontend
ipv6	Turn on support of IPv6
java	Enable Zabbix Java JMX Management Gateway
libxml2	Use libxml2 client library
odbc	Enable Database Monitor and use UnixODBC Library by default
openipmi	Enable openipmi things
openssl	Use dev-libs/openssl as TLS backend
proxy	Enable proxy support
server	Enable zabbix server
ssh	SSH v2 based checks
static	Build statically linked binaries

zmap

mongo	Add support for storing in a mongo DB via dev-db/mongodb
redis	Add support for storing in a redis DB via dev-libs/hiredis

net-dialup

accel-ppp

ipoe	Build IPoE kernel module
libtomcrypt	Support crypto algorithms through dev-libs/libtomcrypt instead of dev-libs/openssl
shaper	Support for traffic shaping

freeradius

memcached	Include dev-libs/libmemcached in caching drivers
mongodb	Include support for MongoDB database
redis	Include support for Redis database

freeradius-client

scp	Add service type hints derived from username prefix
shadow	Enable shadow password support

mgetty

fax	Enables fax support
fidonet	Enables FidoNet support

ppp

activefilter	Enables active filter support
gtk	Installs GTK+ password prompting program that can be used by passprompt.so PPP plugin for reading the password from a X11 input terminal

xl2tpd

kernel	Enable kernel interface for PPPoL2TP

net-dns

avahi

autoipd	Build and install the IPv4LL (RFC3927) network address configuration daemon
bookmarks	Install the avahi-bookmarks application (requires dev-python/twisted)
gtk	Use gtk3 for the avahi utilities to build the avahi-ui-gtk3 library
howl-compat	Enable compat libraries for howl
mdnsresponder-compat	Enable compat libraries for mDNSResponder

bind

dlz	Enables dynamic loaded zones, 3rd party extension
dnsrps	Enable the DNS Response Policy Service (DNSRPS) API, a mechanism to allow an external response policy provider
dnstap	Enables dnstap packet logging
doh	Enables dns-over-https
fixed-rrset	Enables fixed rrset-order option
geoip2	Enable GeoIP2 API from MaxMind
gssapi	Enable gssapi support
json	Enable JSON statistics channel
lmdb	Enable LMDB support to store configuration for 'addzone' zones

bind-tools

gssapi	Enable gssapi support

ddclient

examples	Install various example files, like for cron.

djbdns

ipv6	Apply Fefe's patch (https://www.fefe.de/dns/) for ipv6 support.

dnsdist

bpf	Enable support for eBPF socket filtering
dnscrypt	Enable the ability to act as a DNSCrypt server
dnstap	Enable support for dnstap
doh	Enable support for dns over http via net-libs/nghttp2
doh3	Enable support for dns over http3 via net-libs/quiche
ipcipher	Enable support for ipcipher via dev-libs/openssl
lmdb	Enable support for lmdb
quic	Enable support for dns over quic via net-libs/quiche
regex	Enable support for regular expression matching via dev-libs/re2
remote-logging	Enable support for remote logging via dev-libs/protobuf
ssl	Enable support for and encrypted client-server communication via dev-libs/libsodium
web	Enable support for the web UI
xdp	Enable support for AF_XDP high performance packet processing

dnsmasq

auth-dns	Add support for acting as an authorative DNS server.
conntrack	Add support for Linux conntrack connection marking.
dhcp	Enable support for acting as a DHCP server.
dhcp-tools	Install extra command line tools for manually managing DHCP leases.
dnssec	Enable support DNSSEC validation and caching.
dumpfile	Include code to dump packets to a libpcap-format file for debugging
id	Whether report *.bind CHAOS info to clients, otherwise forward such requests upstream instead
libidn2	Enable support for Internationalized Domain Names, via net-dns/libidn2 rather than net-dns/libidn
loop	Include functionality to probe for and remove DNS forwarding loops
nettlehash	Use hashing functions from dev-libs/nettle
script	Enable support for calling scripts when leases change.
tftp	Enables built in TFTP server for netbooting.

dnssec-validator

dlv	Enable support for the DNSSEC look-aside validation
nsec3	Enable support for the NSEC3 Resource Record

getdns

getdns-query	Add getdns_query tool
getdns-server-mon	Add getdns_server_mon tool
libev	Enable dev-libs/libev support
libevent	Enable dev-libs/libevent support
libuv	Enable dev-libs/libuv support
stubby	Add Stubby DNS Privacy Deamon
unbound	Enable net-dns/unbound libraries support

hash-slinger

ipsec	Enable support for IPSECKEY records (ipseckey)
openpgp	Enable support for OPENPGPKEY records (openpgpkey)
ssh	Enable support for SSHFP records (sshfp)

idnkit

liteonly	Compile and install lite library only

inadyn

mbedtls	Use net-libs/mbedtls as tls provider.
openssl	Use dev-libs/openssl as tls provider.

knot

cookies	Enable the DNS cookie module (RFC 7873)
dnsproxy	Enable the tiny DNS proxy module
dnstap	Include support for the dnstap binary log format (http://dnstap.info/)
doh	Enable DNS over HTTP (DoH) using libnghttp2
fastparser	Use a zone file parser that is faster, but requires more memory and CPU time to compile
geoip	Enable the Geography-based responses module
libidn2	If IDN support is enabled, use net-dns/libidn2 instead of net-dns/libidn
noudp	Enable the module which can send empty truncated responses to UDP queries
onlinesign	Enable the module that sign zones on the fly instead of pre-signing zone
queryacl	Enable the module for query access control
quic	Enable the DNS over QUIC (DoQ) module using libngtcp2
rrl	Enable the response rate limiting module
stats	Enable the server statistics module
synthrecord	Enable the automatic forward/reverse records module
utils	Install Knot utilities, such as kdig, kzonecheck, ...
whoami	Enable the whoami response module
xdp	Enable eXpress Data Path

knot-resolver

dnstap	Build dnstap binary logging module
kresc	Build (experimental) command-line client
nghttp2	DNS-over-HTTPS support

nsd

bind8-stats	Enables BIND8 like NSTATS and XSTATS and statistics in nsd-control
default-znow	Enable full relocation binding at load-time (RELRO NOW, to protect GOT and .dtor areas)
dnstap	Enable the structured binary log format
ipv6	Enable IPv6 support
largefile	Enables support for large files
libevent	Use libevent or libev, useful when zone count is high
memclean	Cleanup memory (at exit) for eg. valgrind, memcheck
minimal-responses	If minimal responses are disabled, responses are more likely to get truncated, resulting in TCP fallback
mmap	Use mmap(2) instead of malloc(3); currently experimental
munin	Install a plugin for net-analyzer/munin to graph statistical data from nsd
nsec3	Enable NSEC3 support
packed	Enable packed structure alignment; uses less memory but has unaligned reads
radix-tree	Use a radix tree for main lookups instead of a red-black tree
ratelimit	Enables ratelimiting, based on query name, type and source
recvmmsg	Enable recvmmsg and sendmmsg compilation, faster but some kernel versions may have implementation problems for IPv6
simdzone	Leverage SIMD instructions in modern CPUs to improve throughput
tfo	Enable TCP Fast Open
year2038	Enables support for 64-bit 'time_t' (sets D_TIME_BITS=64; glibc only)

opendnssec

external-hsm	Enables support for storing DNSSEC keys through an arbitrary non-portage PKCS#11 interface, specified through an environment variable
opensc	Enables support for storing DNSSEC keys through a dev-libs/opensc PKCS#11 interface
signer	Enables signing capabilities for OpenDNSSEC
softhsm	Enables support for storing DNSSEC keys in a dev-libs/softhsm PKCS#11 object

pdns

lmdb	Use LMDB as backend.
lua-records	Enable LUA records.
remote	Use a generic socket or pipe as a backend (via JSON RPC requests).
sodium	Use dev-libs/libsodium for cryptography
tinydns	Use a TinyDNS CDB database as backend.
tools	Build optional tools (dnsscan, dnsscope, etc..).

pdns-recursor

dnstap	Enable support for dnstap
sodium	Use dev-libs/libsodium for cryptography

pdnsd

urandom	Linux-only: use /dev/urandom (pseudo-random number generation) instead of the default use of random() PRNG.

rbldnsd

ipv6	Support listening on ipv6 addresses and ipv6 database entries.

resolvconf-symlink

symlink	Actually replace /etc/resolv.conf with a symlink. Without this flag, the ebuild is a no-op.

unbound

dnscrypt	Enable DNSCrypt support
dnstap	Enable dnstap support
ecdsa	Enable ECDSA support
ecs	Enable EDNS client subnet support
gost	Enable GOST support
http2	Enable HTTP/2 support for DoHnet-libs/nghttp2
redis	Enable cache db backend which usesdev-libs/hiredis
tfo	Enable TCP Fast Open client+server

net-firewall

arno-iptables-firewall

plugins	Install optional plugins
rsyslog	Install configuration snippet for app-admin/rsyslog

conntrack-tools

cthelper	Use net-libs/libnetfilter_cthelper for userspace conntrack helper support
cttimeout	Use net-libs/libnetfilter_cttimeout for conntrack timeout support

ebtables

perl	Install the ebtables-save script which uses perl

firehol

ipset	Use net-firewall/ipset.

firewalld

iptables	Add support for net-firewall/iptables as firewall backend
nftables	Add support for net-firewall/nftables as firewall backend

fwknop

client	Build fwknop client
extras	Install utility scripts and AppArmor policy for fwknopd
firewalld	Use net-firewall/firewalld as the default server backend
gdbm	Use sys-libs/gdbm to store fwknopd digest cache
gpg	Enable GPG support via app-crypt/gpgme
iptables	Use net-firewall/iptables as the default server backend
nfqueue	Enable UDP-only NFQUEUE server mode (no net-libs/libpcap dependency)
server	Build fwknopd server
udp-server	Enable UDP-only server mode (no net-libs/libpcap dependency)

ipt_netflow

natevents	Netflow NAT translation events (NEL) support

iptables

conntrack	Build against net-libs/libnetfilter_conntrack when enables the connlabel matcher
netlink	Build against libnfnetlink which enables the nfnl_osf util
nftables	Support nftables kernel interface
pcap	Build against net-libs/libpcap which enables the nfbpf_compile util

nftables

doc	Create man pages for the package (requires app-text/asciidoc)
json	Enable JSON support via dev-libs/jansson
xtables	Add libxtables support to try to automatically translate rules added by iptables-compat

pglinux

cron	Install cron script

shorewall

init	Adds the capability to place the firewall in a safe state prior to bringing up the network interfaces
ipv4	Installs everything needed to create a full IPv4 firewall
ipv6	Adds the capability to create a full IPv6 firewall (requires net-firewall/shorewall ipv4 USE flag)
lite4	Installs everything needed to just *run* an IPv4 compiled firewall script created with net-firewall/shorewall ipv4 USE flag
lite6	Installs everything needed to just *run* an IPv6 compiled firewall script created with net-firewall/shorewall ipv6 USE flag

ufw

examples	Example ufw config files
ipv6	IPv6 support for iptables

net-fs

autofs

dmalloc	Enable debugging with the dmalloc library
ldap	Install LDAP module
libtirpc	Use TiRPC library instead of SunRPC
mount-locking	Enable locking to prevent corruption of /etc/mtab in the presence of concurrent auto-mounting. If enabled, recursive auto-mounting (eg. using autofs to bind or loop mount a filesystem which is itself auto-mounted) is not possible.
sasl	Enable SASL support in the LDAP module

cifs-utils

ads	Enable Active Directory support and create cifs.idmap binary - idmap support
caps	Enable sys-libs/libcap-ng support
creds	cifs credentials support
python	Enable support for python and install python tools

cvmfs

server	Install the cvmfsd program and init script

libnfs

utils	Build/install nfs-{cat,ls,cp} utils

netatalk

pgp	Add support pgp authentication module
quota	Add support for user quota on various filesystems
shadow	Add shadow support
ssl	Use dev-libs/openssl to provide DHX User Access Modules. These are not used with most recent versions of OS X and can be kept disabled without risks.
tracker	Add support for spotlight like tracker

nfs-utils

junction	Enable NFS junction support in nfsref
ldap	Add ldap support
libmount	Link mount.nfs with libmount
nfsv3	Enable support for NFSv2 and NFSv3
nfsv4	Enable support for NFSv4 (includes NFSv4.1 and NFSv4.2)
uuid	Support UUID lookups in rpc.mountd

openafs

apidoc	Build API documentation using app-text/doxygen. May take a *long* time to build.
bitmap-later	Enable fast startup of file server by not reading bitmap till needed.
fuse	Build fuse client.
kauth	Install the DEPRECATED kauth server, PAM modules, and utilities
modules	Build libafs kernel module. Disable only if you know what you're doing: without this module OpenAFS client will not work.
namei	Enable namei fileserver instead of inode fileserver. You should disable this option only if compatibility with inode format AFS storage is required.
pthreaded-ubik	Enable installation of pthreaded ubik applications.
supergroups	Enable support for nested pts groups.
tsm	Enable use of the Tivoli TSM API libraries from app-backup/tsm for butc support. AMD64 only.
ubik-read-while-write	Enable vlserver read from db cache during write locks (EXPERIMENTAL)

s3backer

nbd	Support export as an nbd device

s3fs

gnutls	Enable net-libs/gnutls crypto backend
nettle	Use dev-libs/nettle network functions with GnuTLS.
nss	Enable dev-libs/nss crypto backend

samba

addc	Enable Active Directory Domain Controller support
ads	Enable Active Directory support
ceph	Enable support for Ceph distributed filesystem via sys-cluster/ceph
client	Enables the client part
cluster	Enable support for clustering
glusterfs	Enable support for Glusterfs filesystem via sys-cluster/glusterfs
gpg	Use app-crypt/gpgme for AD DC
iprint	Enabling iPrint technology by Novell
json	Enable json audit support through dev-libs/jansson
lmdb	Enable LMDB backend for bundled ldb
profiling-data	Enables support for collecting profiling data
quota	Enables support for user quotas
regedit	Enable support for regedit command-line tool
snapper	Enable vfs_snapper module (requires sys-apps/dbus)
spotlight	Enable support for spotlight backend
system-heimdal	Use app-crypt/heimdal instead of bundled heimdal.
system-mitkrb5	Use app-crypt/mit-krb5 instead of app-crypt/heimdal.
unwind	Enable libunwind usage for backtraces
winbind	Enables support for the winbind auth daemon

net-ftp

frox

transparent	Enable transparent proxying of data connections

ftpbase

zeroconf	Enable support for zero-configuration networking via Avahi.

lftp

convert-mozilla-cookies	Install the convert-mozilla-cookies script and its run-time dependencies
verify-file	Install the verify-file script and its run-time dependencies

proftpd

authfile	Enable support for the auth-file module
ban	Enable support for the mod_ban module
case	Enable support for the mod_case module
copy	Enable support for the mod_copy module
ctrls	Enable support for the mod_ctrls and mod_ctrls_admin modules
deflate	Enable support for the mod_deflate module
diskuse	Enable support for the mod_diskuse module
dso	Enable support for the mod_dso module
dynmasq	Enable support for the mod_dynmasq module, for dynamically updating MasqueradeAddress for dyndns-like scenarios)
exec	Enable support for the mod_exec module. WARNING: this could be a security risk
ident	Enable support for the mod_ident module
ifsession	Enable support for the ifsession module
ifversion	Enable support for the mod_ifversion module
log-forensic	Enable support for the mod_log_forensic module, log only suspicious actions.
memcache	Enable support for the mod_memcache module, for using memcached servers
msg	Enable support for the mod_msg module, allows system users to send messages to connected clients via the ftpdctl program.
qos	Enable support for the mod_qos module
ratio	Enable support for the mod_ratio module
readme	Enable support for the mod_readme module
rewrite	Enable support for the rewrite module
sftp	Enable support for the mod_sftp module and optionally mod_sftp_sql and mod_sftp_pam if matching USE flags are enabled
shaper	Enable support for the mod_shaper module
sitemisc	Enable support for the sitemisc module
sodium	Use dev-libs/libsodium for password encryption an key exchange
softquota	Enable support for the quotatab module
unique-id	Enable support for the mod_unique_id module, every connection gets unique ID.
vroot	Enable support for the virtual root module

pure-ftpd

anondel	Permit anonymous to delete files
anonperm	Permit anonymous to change file permissions
anonren	Permit anonymous to rename files
anonres	Permit anonymous to resume file transfers
implicittls	Enable TLS on Port 990
noiplog	Disables logging of IP addresses
paranoidmsg	Display paranoid messages instead of normal ones
resolveids	Resolve UIDs/GIDs
sysquota	Enables system quota support (needs sys-fs/quota)
vchroot	Enable support for virtual chroot (possible security risk)

tftp-hpa

client	Compile and install the tftp client
server	Compile and install the tftp server

yafc

ssh	Build with SFTP support

net-im

biboumi

udns	Asynchronously resolve domain names using net-libs/udns

bitlbee

libevent	Use libevent for event handling
nss	Prefer dev-libs/nss as SSL/TLS provider
otr	Enable support for encrypted conversations
plugins	Enable support for plugins
purple	Use libpurple instead of the built-in IM protocol support
twitter	Enable Twitter protocol support

coturn

mongodb	Enable support for the mongodb database
redis	Enable support for the redis database

dino

gpg	Enable OpenPGP encryption plugin
http	Enable HTTP file upload plugin
notification-sound	notification sounds plugin
omemo	Enable OMEMO encryption plugin
rtp	Enable Audio/Video calls over XMPP using RTP

ejabberd

captcha	Support for CAPTCHA Forms (XEP-158) on registration
full-xml	Use XML features in XMPP stream (ex: CDATA), requires XML compliant clients
mssql	Enable Microsoft SQL Server support (via ODBC) for data storage
mysql	Enable MySQL support for data storage
odbc	Enable ODBC support to access data storage
postgres	Enable PostgreSQL support for data storage
redis	Enable Redis support for transient data
roster-gw	Turn on workaround for processing gateway subscriptions
sip	Enable SIP support
sqlite	Enable SQLite database support
stun	Enable STUN/TURN support
zlib	Enable Stream Compression (XEP-0138) using zlib

err

irc	Pull optional dependencies, needed for IRC backend

gajim

crypt	End to end encryption and GPG encryption
geolocation	Sharing your location
jingle	Audio and video calls
omemo	Install dependencies for OMEMO encryption plugin
remote	Controling Gajim instance from command line with gajim-remote
rst	Generating XHTML output from RST code
spell	Spellchecking of composed messages
upnp	Ability to request your router to forward port for file transfer
webp	Support WebP avatars

libcommuni

qml	Install optional qml files.
uchardet	Use app-i18n/uchardet, which is upstreams default, instead of dev-libs/icu, which makes impossible to run tests.

pidgin

gadu	Enable Gadu Gadu protocol support
groupwise	Enable Novell Groupwise protocol support
gstreamer	Enables voice and video sessions
gtk	Builds Pidgin, the GTK+ interface
meanwhile	Enable meanwhile support for Sametime protocol
ncurses	Build finch, console interface
prediction	Enable Contact Availability Prediction plugin
python	Build libgnt (GLib Ncurses Toolkit used by finch) with python scripting support
xscreensaver	Use X screensaver protocol extension to monitor idle/active status based on mouse/keyboard events
zephyr	Enable Zephyr protocol support

profanity

gpg	Enable OpenPGP encryption
omemo	Enable OMEMO encryption
omemo-qrcode	Enable exchanging OMEMO information via QR code
otr	Enable encrypted conversations using Off-The-Records messaging
python	Enable Python plugins support

prosody

libevent	Use libevent for event handling

psi

aspell	Enable spellchecking using app-text/aspell
enchant	Enable spellchecking using app-text/enchant
extras	Enable Psi+ patchset
hunspell	Enable spellchecking using app-text/hunspell
iconsets	Install additional iconsets, some of them have no clear licensing
webengine	Enable themed, html-based chatlogs using dev-qt/qtwebengine
whiteboarding	Enable experimental interactive SVG drawing
xscreensaver	Use X screensaver protocol extension to monitor idle/active status based on mouse/keyboard events

psimedia

extras	Enable Psi+ mode (required when built for Psi+)

qtox

X	Enable auto-away support
spellcheck	Enable spell checking support

spectrum2

frotz	Enables the Z-Engine backend.
irc	Enables the IRC backend, based on net-im/libcommuni.
purple	Enables the libpurple backend, based on net-im/pidgin.
sms	Enables the SMS backend, based on app-mobilephone/smstools.
twitter	Enables the Twitter backend.
whatsapp	Enables the WhatsApp backend, based on net-im/transwhat.

telegram-desktop

enchant	Use the app-text/enchant spell-checking backend instead of app-text/hunspell
fonts	Use builtin patched copy of open-sans fonts (overrides fontconfig)
libdispatch	Use dev-libs/libdispatch to speed up concurrent code execution
qt6	Build with Qt6 support
qt6-imageformats	Add support for HEIF, AVIF and JpegXL by bundling kde-frameworks/kimageformats

tkabber

plugins	Enables installation the extra plugins

tokodon

mpv	Use media-libs/mpvqt instead of dev-qt/qtmultimedia for video playback (default)
webengine	Use dev-qt/qtwebengine for built-in authentication page (default is external browser)

toxic

audio-notify	Enables native sound notifications
experimental	Use experimental features in net-libs/tox
games	Enables some small mini-games
llvm	Enables support for LLVM Address Sanitizer
notification	Enables desktop notifications with libnotify, with sound support.
qrcode	Enables QR code support
sound	Enables audio calling
video	Enables video calling

zoom

bundled-qt	Use bundled Qt and icu instead of system-wide libs
opencl	Use OpenCL for virtual background support (virtual/opencl)
zoom-symlink	Install a zoom symlink in /usr/bin

net-irc

anope

ldap	Build LDAP modules for e.g. opertypes
sql	Build modules which require SQL
ssl	Provide SSL services using OpenSSL
tre	Use dev-libs/tre for regular expressions

atheme-services

cracklib	Enable nickserv/cracklib module for enforcing strong account passwords
largenet	Enable support/tweaks for large networks
ldap	Enable ldap-backed authentication module
perl	Install a perl module which wraps around the services' XML-RPC interface

epic5

archive	Use app-arch/libarchive to use zip and tar archives from scripts.

hexchat

libcanberra	Enable sound event support using media-libs/libcanberra
plugin-checksum	Build Checksum plugin (needs plugins)
plugin-fishlim	Build FiSHLiM plugin (needs plugins )
plugin-sysinfo	Build SysInfo plugin (needs plugins)
theme-manager	Build the theme manager (mono)

inspircd

argon2	Enable Argon2 hashes in modules
gnutls	Enable TLS support
ldap	Enable LDAP support
log-json	Enable logging via JSON
maxminddb	Add support for geolocation using libMaxMindDB
mbedtls	Add support for TLS using the mbedTLS library
mysql	Enable MySQL database backend
pcre2	Add support for Perl Compatible Regular Expressions 2
postgres	Enable PostgreSQL database backend
re2	Add support for Google RE2 regular expressions library
regex-posix	Add support for POSIX Regular Expressions
regex-stdlib	Add support for C++ stdlib regular expressions
sqlite	Enable Sqlite database backend
ssl	Enable SSL support
sslrehashsignal	Enable rehashing SSL module by SIGUSR1
tre	Enable support for TRE, a lightweight, robust, and efficient POSIX compliant regexp matching library

iroffer-dinoex

admin	Compile with HTTP Admin
blowfish	Compile with blowfish encryption support
chroot	Compile with chroot support
http	Compile with HTTP server support
memsave	Compile with memory protection
telnet	Compile with Telnet server support

irssi

otr	Adds support for a loadable IRC otr module
proxy	Adds support for a loadable IRC proxy module

kvirc

webengine	Support Qt WebEngine

limnoria

crypt	Enables user authentication with GPG

ngircd

ident	Enables support for net-libs/libident
irc-plus	Enables support for the IRC+ protocol (needs virtual/libiconv)
strict-rfc	Strict RFC compliance; may harm compatibility

psybnc

multinetwork	Adds support for multiple networks
oidentd	Adds support for oidentd
scripting	Adds scripting support

quassel

bundled-icons	Use icon themes bundled with Quassel, rather than depending on system packages.
crypt	Support core->network per-channel and per-query blowfish encryption via app-crypt/qca SLOT 2.
dbus	Support desktop notifications via the StatusNotifier D-Bus service (used by most modern desktop environments).
gui	Build the Qt5 GUI client for quassel. If this USE flag is disabled, the GUI is not built, and cannot be used. You might want to disable this on the server, but you need it enabled on the client.
monolithic	Build standalone client with integrated core, no external quasselcore needed. Only useful if you don't want to use Quassel's client/server model. The server and X flags are not needed in this case but it is possible to enable them too.
oxygen	Support the Oxygen icon set that was the default for KDE4.
server	Build the server binary. If this USE flag is disabled, the 'core' server binary for quassel is not built, and cannot be used. You need this enabled on the server, but you might want to disable it on the client.
urlpreview	Use QtWebEngine rendering engine for showing URL thumbnails.

rbot

aspell	Use aspell instead of ispell in the "spell" plugin for rbot. The vanilla plugin uses ispell, but enabling this flag makes it use the ispell interface from aspell instead.
cal	Add dependency over a package providing the /usr/bin/cal command, which is needed to enable the "cal" plugin for rbot. If the USE flag is disabled the plugin is also disabled by default.
figlet	Add dependency over app-misc/figlet, which is used by the "figlet" plugin for rbot. If the USE flag is disabled the plugin will be unable to use figlet; if toilet is also disabled, the plugin will be disabled.
fortune	Add dependency over games-misc/fortune-mod, which is needed to enable the "fortune" plugin for rbot. If the USE flag is disabled the plugin is also disabled by default.
host	Add dependency over net-dns/bind-tools (providing /usr/bin/host), which is needed to enable the "host" plugin for rbot. If the USE flag is disabled the plugin is also disabled by default.
nls	Build and install translation for the messages coming from the bot and its plugins (through dev-ruby/ruby-gettext).
timezone	Add dependency over dev-ruby/tzinfo to enable the "time" plugin for rbot. If the USE flag is disabled the plugin is also disabled by default.
toilet	Add dependency over app-misc/toilet, which is used by the "figlet" plugin for rbot. If the USE flag is disabled the plugin will be unable to use toilet; if figlet is also disabled, the plugin will be disabled.
translator	Add dependency over dev-ruby/mechanize, which is needed to enable the "translator" plugin for rbot. If the USE flag is disabled the plugin is also disabled by default.

soju

moderncsqlite	Use moderncsqlite, a cgo-free port of SQLite

unrealircd

class-nofakelag	Enable an unsupported class::options flag called “nofakelag” allowing you to grant fakelag exemption to normal user (instead of just opers).
operoverride	Enable OperOverride extension
operoverride-verify	Enable requiring opers to invite themselves to +s/+p channels
prefixaq	Enable chanadmin and chanowner prefixes
showlistmodes	Display channel modes in /LIST (only configured at compiletime)

weechat

alias	Enable plugin for alias control
buflist	Enable buflist plugin
charset	Enable encoding conversions
enchant	Enable spell checker plugin via Enchant instead of GNU Aspell
exec	Enable exec plugin
fifo	Enable FIFO support (sh pipes)
fset	Enable fast set plugin
irc	Enable IRC protocol support
logger	Enable support for logging
relay	Enable relay plugin (experimental)
relay-api	Enable json API support for the relay plugin (experimental)
scripts	Build infrastructure for scripting
trigger	Enable trigger plugin
typing	Enable typing plugin
xfer	Enable xfer plugin support

znc

argon2	Store password hashes using Argon2id instead of SHA-256
zlib	Enable mod_deflate-like gzip support for znc's web interface using sys-libs/zlib.

net-libs

aqbanking

ebics	Enable support for Electronic Banking Internet Communication Standard (EBICS)

axtls

cgi-lua	Enables lua backed cgi for axhttpd server
cgi-php	Enables php backed cgi for axhttpd server
httpd	Enables axhttpd web server component
static	Statically build axhttpd server

c-client

chappa	Enable Eduardo Chappa's patches for use with mail-client/alpine (mainly adds support for maildir)
doc	Install RFCs related to IMAP
topal	Enable support for net-mail/topal for use with mail-client/alpine

canlock

header-parser	Build article header parsers
legacy	Build legacy API (v2 compatible)

cvm

vpopmail	Enable vpopmail support

czmq

drafts	Build draft API, which may change at any time without any notice, and is therefore not recommended for normal use. (requires draft support in net-libs/zeromq as well)
http-client	Build support for HTTP client using net-misc/curl
http-server	Build support for HTTP server using net-libs/libmicrohttpd
nss	Use dev-libs/nss for SHA instead of an internal implementation
uuid	Enable UUID support using sys-apps/util-linux

daq

afpacket	Build the AFPacket data acquisition module. Functions similar to the PCAP module but with better performance. Snort can run unprivileged when using this module. AFpacket supports both inline and passive modes.
dump	Build the Dump data acquisition module. The dump DAQ allows you to test the various inline mode features available in 2.9 Snort like injection and normalization.
ipq	Build the IPQ data acquisition module. IPQ is the old way to process iptables packets for inline deployments. Snort can not run unprivileged when using this module.
nfq	Build the NFQ data acquisition module. NFQ is the new way to process iptables packets for inline deployments. Snort can not run unprivileged when using this module.
pcap	Build the PCAP data acquisition module.

davix

tools	Install additional tools

freaklabs-chibiarduino

promisc	Enable promisc in the config file for packet sniffing

glib-networking

gnome	Extract HTTP/HTTPS/SOCKS proxy configuration stored using GSettings
libproxy	Use net-libs/libproxy for getting the HTTP/HTTPS/SOCKS proxy configuration

gloox

xhtmlim	expose internal NodeList for optional XHTML-IM rendering without external parser

gnome-online-accounts

gnome	Use gnome-base/gnome-control-center to set GNOME online accounts preferences
ms365	Enable Microsoft 365 provider

gnutls

dane	Build libgnutls-dane, implementing DNS-based Authentication of Named Entities. Requires net-dns/unbound
openssl	Build openssl compatibility libraries
pkcs11	Add support for PKCS#11 through app-crypt/p11-kit
sslv2	Support for the old/insecure SSLv2 protocol
sslv3	Support for the old/insecure SSLv3 protocol
test-full	Enable full test mode
tls-heartbeat	Enable the Heartbeat Extension in TLS and DTLS
tools	Build cli tools such as gnutls-cli, certtool and oscptool

gssdp

man	Generate man page for tools

libetpan

liblockfile	Enable support for liblockfile library
lmdb	Use dev-db/lmdb as cache DB

libgsasl

gcrypt	Use dev-libs/libgcrypt for low-level crypto
ntlm	Add support for Microsoft's NTLM mechanism using net-libs/libntlm

libiio

aio	Enable asynchronous IO support

libiscsi

rdma	Enable infiniband support via sys-cluster/rdma-core

libisds

openssl	Use dev-libs/openssl as crypto backend instead of app-crypt/gpgme and dev-libs/libgcrypt

libktorrent

xfs	Enable XFS specific disk preallocation support via sys-fs/xfsprogs

libmicrohttpd

epoll	Support epoll() system call
eventfd	Use EventFD for efficient inter-thread communication
thread-names	Assign thread names to internal threads, useful for dependent apps debugging

libnids

glib	Use dev-libs/glib for multiprocessing support
libnet	Include code requiring net-libs/libnet

libnma

pkcs11	Enable PKCS#11 support in certificate chooser via app-crypt/gcr

liboauth

curl	If enabled, net-misc/curl is used thorugh the libcurl library; if it's not, the curl command is used instead. Some features are only available when using the library, but using it as library requires matching SSL implementations.

liboping

filecaps	Allow non-root users to use [n]oping utility.
ncurses	Build ncurses-based version of oping utility (requires sys-libs/ncurses)

libpcap

netlink	Use dev-libs/libnl to put wireless interfaces in monitor mode.
rdma	Enable RDMA capture support using sys-cluster/rdma-core
remote	Enable remote packet capture which may expose libpcap-based applications to attacks by malicious remote capture servers!
yydebug	Enable parser debugging code

libprotoident

tools	Build and install command-line tools

libproxy

duktape	Use dev-lang/duktape for PAC parsing
gnome	Enable support for reading proxy settings from GNOME

libqmi

mbim	Support QMI over Mobile Broadband Interface Model (MBIM)
qrtr	Support QMI over IPC Router bus (QRTR)

libsoup

gssapi	Enable GSSAPI support
samba	Use net-fs/samba for NTLM Single Sign-On
sysprof	Enable profiling data capture support using dev-util/sysprof-capture

libsrtp

aesicm	Use AES ICM cryptographic algorithm
console	Use /dev/console instead of stdout for error messages
nss	Use NSS crypto primitives
openssl	Use OpenSSL crypto primitives
syslog	Use syslog for error messages

libssh

gcrypt	Use dev-libs/libgcrypt as TLS provider
gssapi	Enable gssapi support
mbedtls	Use net-libs/mbedtls as TLS provider
pcap	Build with PCAP output support
server	Build with SSH server support
sftp	Build with SFTP support

libssh2

gcrypt	Use dev-libs/libgcrypt instead of dev-libs/openssl
mbedtls	Use net-libs/mbedtls instead of dev-libs/openssl

libtorrent-rasterbar

dht	Enable DHT (distributed hash table) support

libtrace

numa	Use sys-process/numactl

libupnp

blocking-tcp	Do not use async socket calls
reuseaddr	Allow clean restarts by binding the socket with SO_REUSEADDR
samples	Install sample applications

libvncserver

24bpp	Enable 24bpp support
filetransfer	Enable support for TightVNC's file transfer protocol
lzo	Enable LZO support via dev-libs/lzo instead of using internal miniLZO implementation

libwebsockets

access-log	Support generating Apache-compatible access logs
client	The client part of the library and libwebsockets-test-client
extensions	Compile with extensions (permessage-deflate)
generic-sessions	With the Generic Sessions plugin
http-proxy	Support for rewriting HTTP proxying
ipv6	Compile without support for ipv6
lejp	With the Lightweight JSON Parser
libev	Support event loops via dev-libs/libev
libevent	Support event loops via dev-libs/libevent
libuv	Support asynchronous I/O via dev-libs/libuv
mbedtls	Use mbedTLS replacement for OpenSSL
peer-limits	Track peers and restrict resources a single peer can allocate
server-status	Support json + jscript server monitoring
smtp	Provide SMTP support
sqlite3	Require SQLITE3 support

loudmouth

asyncns	Use net-libs/libasyncns for asynchronous name resolution.
openssl	Enable dev-libs/openssl support instead of gnutls (which is the default).

mbedtls

cmac	Enable block cipher-based message authentication code algorithm
havege	Enable the HAVEGE random generator. Warning: the HAVEGE random generator is not suitable for virtualized environments
programs	Build Mbed TLS programs

neon

libproxy	Add support for net-libs/libproxy
pkcs11	Add support for PKCS#11 using dev-libs/pakchois

nghttp2

hpack-tools	Install HPACK (header compression) helper tools
utils	Install nghttp, nghttpd and nghttpx

ngtcp2

openssl	Provide SSL support using OpenSSL (requires dev-libs/openssl)

nodejs

corepack	Enable the experimental corepack package management tool
inspector	Enable V8 inspector
npm	Enable NPM package manager
pax-kernel	Enable building under a PaX enabled kernel
snapshot	Enable snapshot creation for faster startup
system-icu	Use system dev-libs/icu instead of the bundled version
system-ssl	Use system OpenSSL instead of the bundled one
systemtap	Enable SystemTap/DTrace tracing

ntirpc

gssapi	Include support for RPCSEC GSS
rdma	Include support for RDMA RPC

paho-mqtt-c

high-performance	The debugging aids internal tracing and heap tracking are not included

pjproject

amr	Inlcude AMR codec in the build
epoll	Use /dev/epoll ioqueue on Linux (experimental)
g711	Include G.711 codecs in the build
g722	Include G.722 codec in the build
g7221	Include G.722.1 codec in the build
g729	Include G.729 codec via net-libs/bcg729
ilbc	Include iLBC codec in the build
l16	Include Linear/L16 codec family in the build
libyuv	Include libyuv in the build
openh264	Include Open H.264 support in the build
resample	Include resampling implementations in the build
silk	Include SILK support in the build
srtp	Enable support for encrypted voice transmission (secure RTP)
v4l2	Include Video4Linux v2 support in the build
vpx	Include VP8 and VP9 codec support in the build
webrtc	Enable WebRTC support

qxmpp

omemo	Enable OMEMO encryption

rabbitmq-c

tools	Builds cli tools to interact with brokers

rtrlib

ssh	Enable SSH support

shairplay

playfair	Add support for handling fairplay handshake (used in for example screen mirroring)

tox

av	Adds support for audio and video.
daemon	Enable the DHT Bootstrap Daemon.
dht-node	Enables DHT Bootstrap Node.
experimental	Enables the experimental api
key-utils	Builds utilities to create custom keys and profiles
log-debug	Log level: 4
log-error	Log level: 1
log-info	Log level: 3
log-trace	Log level: 5
log-warn	Log level: 2

udns

tools	Build and install dnsget, ex-rdns and rblcheck tools

wandio

http	Build support for reading files over HTTP using net-misc/curl

webkit-gtk

examples	Install the MiniBrowser example application
gamepad	Enable gamepad input support via dev-libs/libmanette
jumbo-build	Combine source files to speed up build process

wvstreams

boost	Use dev-libs/boost to provide TR1-compatible functional interface. This USE flag is only needed with GCC earlier than version 4.1, or with other compilares not providing said interface.

xdp-tools

tools	Install various helper tools rather than just libxdp.

xrootd

ceph	Enable suport for sys-cluster/ceph (XrdCeph plugin)
fuse	Enable the sys-fs/fuse filesystem driver
http	Enable http protocol support
libxml2	Use dev-libs/libxml2 for XML parsing (preferred) instead of bundled tinyxml
macaroons	Enable support for macaroons with dev-libs/libmacaroons
scitokens	Enable support for scitokens with dev-cpp/scitokens-cpp
server	Install xrootd server and related plug-ins
xrdec	Enable erasure coding support (XrdEc plugin) with dev-libs/isa-l

zeromq

drafts	Build draft API, which may change at any time without any notice, and is therefore not recommended for normal use.
libbsd	Use strlcpy() from dev-libs/libbsd instead of internal implementation.
sodium	Use dev-libs/libsodium for cryptography

net-mail

courier-imap

trashquota	include deleted messages, and the Trash folder, in the estimated quota usage for maildirs

cyrus-imapd

backup	Enable backup service support
calalarm	Enable CalDAV alarm support
http	Enable http and http/2 support
replication	Enable replication support
server	Enable building server binaries
sieve	Enable sieve support
xapian	Enable Xapian search engine support

dbmail

sieve	Enable sieve filter support

dovecot

argon2	Add support for ARGON2 password schemes
lucene	Add lucene full text search (FTS) support using dev-cpp/clucene
managesieve	Add managesieve protocol support
rpc	Add support for NFS quotas
sieve	Add sieve support
solr	Add solr full text search (FTS) support
stemmer	Add libstemmer support (for FTS)
textcat	Add libtextcat language guessing support for full text search (FTS)

fetchmail

socks	Enable support for socks proxy
tk	Enable support for Tk GUI toolkit, in particular it installs fetchmailconf

gnubiff

password	Enable save passwords to connect mail servers in user space

lbdb

abook	Enables app-misc/abook support
bbdb	Include support for app-emacs/bbdb
evo	Add support for mail-client/evolution
finger	Enables finger support

mailutils

clients	Build client programs - frm maidag mail sieve messages readmsg dotlock movemail mimeview mh
kyotocabinet	Enable Kyoto Cabinet database support
servers	Build server programs - imap4d pop3d comsatd
tokyocabinet	Enable Tokyo Cabinet database support

mboxgrep

dmalloc	Enable debugging using dev-libs/dmalloc

mu

emacs	Install the mu4e mail client

notmuch

apidoc	Provide doxygen generated API docs
crypt	Support decryption and verification of PGP/MIME messages and in Emacs UI - encryption; support also S/MIME signature verification since version 0.22
doc	Install API documentation
emacs	Install Emacs UI (the main one)
mutt	Install helper script for Mutt
nmbug	Install experimental tag sharing / pseudo-bug-tracking script for Notmuch (see http://notmuchmail.org/nmbug/)

qmailadmin

maildrop	Filter spam using maildrop

tpop3d

authexternal	Enable authentication by an external program
flatfile	Enable authentication against /etc/passwd-style flat files
passwd	Enable /etc/passwd authentication
sha1	Use OpenSSL for sha1 encrypted passwords.
shadow	Enable /etc/shadow authentication

vpopmail

clearpasswd	Enables cleartext password storage in the vpasswd files
ipalias	Enables enable-ip-alias-domains
maildrop	Enables mail-filter/maildrop support in vdelivermail
spamassassin	Enables mail-filter/spamassassin support

net-misc

AQtion

lro	Enable/disable Large Receive Offload. This MUST be disabled for bridging or forwarding.

apt-cacher-ng

fuse	Install the sys-fs/fuse based acngfs, to use a userspace filesystem for the apt cache.

aria2

bittorrent	Enable support for the bittorrent protocol.
gnutls	Use net-libs/gnutls as TLS provider (preferred). Otherwise, dev-libs/openssl will be used as TLS provider. Both apply only with USE=ssl.
libuv	Use dev-libs/libuv backend.
libxml2	Use dev-libs/libxml2 for XML parsing (preferred) instead of dev-libs/expat.
metalink	Enable support for metalink.
nettle	Use dev-libs/nettle for message digests, plus dev-libs/gmp for bittorrent (if enabled). If this flag is disabled, dev-libs/libgcrypt is used instead. This flag is ignored if dev-libs/openssl is used.
scripts	Install additional scripts which use aria2's xmlrpc functionality.
ssh	Enable SFTP support.

asterisk

blocks	Utlize -fblocks (only supported by, and required when using, clang/LLVM)
cluster	Enable high-availability support through the Corosync Cluster Engine
codec2	Enable Codec2 support in asterisk
deprecated	Enable deprecated features (eg, app_macro)
gtalk	Enable support for Google Talk services
http	Enable embedded web server
ilbc	Enable the Internet Low Bitrate Codec (iLBC)
newt	Include additional tools that require redhats windowing toolkit
pjproject	Enable support for pjproject (pjsip)
span	Enable support for the spandsp codec
srtp	Enable support for encrypted voice transmission (secure RTP)
statsd	Enable statsd integration
unbound	Enable improved DNS core (SRV, NAPTR) by use of libunbound

asterisk-core-sounds

alaw	Install the sounds files for the alaw codec.
g722	Install the sounds files for the g722 codec.
g729	Install the sounds files for the g729 codec.
siren14	Install the sounds files for the siren14 codec.
siren7	Install the sounds files for the siren7 codec.
sln16	Install the sounds files for the sln16 codec.
ulaw	Install the sounds files for the ulaw codec.
wav	Install the sounds files for the wav codec.

asterisk-extra-sounds

alaw	Install the sounds files for the alaw codec.
g722	Install the sounds files for the g722 codec.
g729	Install the sounds files for the g729 codec.
gsm	Install the sounds files for the gsm codec.
siren14	Install the sounds files for the siren14 codec.
siren7	Install the sounds files for the siren7 codec.
sln16	Install the sounds files for the sln16 codec.
ulaw	Install the sounds files for the ulaw codec.
wav	Install the sounds files for the wav codec.

asterisk-moh-opsound

alaw	Install the sounds files for the alaw codec.
g722	Install the sounds files for the g722 codec.
g729	Install the sounds files for the g729 codec.
gsm	Install the sounds files for the gsm codec.
siren14	Install the sounds files for the siren14 codec.
siren7	Install the sounds files for the siren7 codec.
sln16	Install the sounds files for the sln16 codec.
ulaw	Install the sounds files for the ulaw codec.
wav	Install the sounds files for the wav codec.

bird

client	Build the ncurses/readline full featured CLI
libssh	Enables net-libs/libssh binding, mendatory for RPKI support

casync

fuse	Enable fuse support

cgminer

ants1	Enable support for Antminer S1 Bitmain
ants2	Enable support for Antminer S2 Bitmain
ants3	Enable support for Antminer S3 Bitmain
avalon	Enable support for Avalon ASICs
avalon-miner	Enable support for Avalon miner ASICs
avalon2	Enable support for Avalon2 ASICs
avalon4	Enable support for Avalon4 ASICs
avalon7	Enable support for Avalon7 ASICs
bab	Enable support for BlackArrow Bitfury
bflsc	Enable support for BFL ASICs
bitforce	Enable support for mining with ButterFly Labs BitFORCE FPGAs
bitfury	Enable support for mining with BitFury ASICs
bitmine_A1	Enable support for mining with Bitmine.ch A1 ASICs
blockerupter	Enable support for mining with BlockRupter ASICs
cointerra	Enable support for mining with Cointerra ASICs
drillbit	Enable support for mining with Drillbit BitFury ASICs
hashfast	Enable support for mining with Hashfast
hashratio	Enable support for mining with Hashratio
icarus	Enable support for mining with Icarus FPGAs
klondike	Enable support for mining with Klondik ASICs
knc	Enable support for mining with KnC miners
minion	Enable support for mining with BlackArrow Bitfury
modminer	Enable support for mining with ModMiner FPGAs
sp10	Enable support for Spondoolies SP10
sp30	Enable support for Spondoolies SP30

chrony

cmdmon	Support for command and monitoring
debug	Get DEBUG_LOG output from chronyd when passing -dd parameter
html	Install HTML documentation
libtomcrypt	Support different hashes via dev-libs/libtomcrypt
nettle	Use dev-libs/nettle for hash functions or nts
nss	Use dev-libs/nss for hash functions
ntp	Support for the Network Time Protocol (NTP)
nts	Support for Network Time Security (NTS). Uses net-libs/gnutls
phc	Support for the PTP (Precision Time Protocol) Hardware Clock (PHC) interface
pps	Support for the Linux Pulse Per Second (PPS) interface
refclock	Support for reference clocks
rtc	Support for the Linux Real Time Clock interface
sechash	Enable support for hashes other than MD5

connman

ethernet	Enable ethernet support.
iptables	Use net-firewall/iptables as firewall.
iwd	Enable wifi support via net-wireless/iwd
l2tp	Use net-dialup/xl2tpd for L2TP VPN support.
nftables	Use net-firewall/nftables as firewall.
ofono	Use net-misc/ofono for telephony support.
openconnect	Use net-vpn/openconnect for VPN support.
openvpn	Use net-vpn/openvpn for openvpn support.
pptp	Use net-dialup/pptpclient for PPTP VPN support.
tools	Enable testing tools.
vpnc	Use net-vpn/vpnc for cisco VPN support.
wireguard	Enable WireGuard VPN support.
wispr	Enable support for WISPr hotspot logins.

connman-gtk

openconnect	Support easier authentication to AnyConnect VPNs

curl

alt-svc	Enable alt-svc support
ftp	Enable FTP support
gnutls	Enable gnutls ssl backend
gopher	Enable Gopher protocol support
hsts	Enable HTTP Strict Transport Security
http3	Enable HTTP/3 support
imap	Enable Internet Message Access Protocol support
mbedtls	Enable mbedtls ssl backend
nghttp3	Enable HTTP/3 support using net-libs/nghttp3
openssl	Enable openssl ssl backend
pop3	Enable Post Office Protocol 3 support
progress-meter	Enable the progress meter
psl	Enable Public Suffix List (PSL) support. See https://daniel.haxx.se/blog/2024/01/10/psl-in-curl/.
quic	Enable support for QUIC (RFC 9000); a UDP-based protocol intended to replace TCP
rtmp	Enable RTMP Streaming Media support
rustls	Enable Rustls ssl backend
smtp	Enable Simple Mail Transfer Protocol support
ssh	Enable SSH urls in curl using libssh2
ssl	Enable crypto engine support (via openssl if USE='-gnutls -nss')
sslv3	Support for the old/insecure SSLv3 protocol
telnet	Enable Telnet protocol support
tftp	Enable TFTP support
websockets	Enable websockets support

dhcp

client	Install the dhclient program
server	Install the dhcpd and dhcrelay programs

dhcpcd

embedded	Embed the definitions of dhcp options in the dhcpcd executable
privsep	Enable support for privilege separation

dibbler

resolvconf	Use resolvconf to handle /etc/resolv.conf updates

dropbear

bsdpty	Add support for legacy BSD pty's rather than dynamic UNIX pty's -- do not use this flag unless you are absolutely sure you actually want it
multicall	Build all the programs as one little binary (to save space)
shadow	Enable shadow password support

dropbox-cli

gpg	Use app-crypt/gpgme to verify signatures

electron-cash

amodem	Enable plugin to support Audio Modem
cli	Enables the CLI interface
cosign	Enable plugin to support multisig wallets between multiple Electrum clients
digitalbitbox	Enable plugin to support Digital Bitbox hardware wallet
email	Enable plugin to support emailing invoices
qrcode	Enable QR code scanning with media-gfx/zbar
sync	Enable plugin to sync wallet metadata across multiple Electrum clients
vkb	Enable plugin for virtual keyboard

electrum

cli	Enables the CLI interface
qrcode	Enable QR code scanning with media-gfx/zbar

electrum-ltc

cli	Enables the CLI interface
qrcode	Enable QR code scanning with media-gfx/zbar

etherdfs

tsr	Install the precompiled TSR program for DOS, which acts as a client.

ethflop

tsr	Build the TSR program for DOS, which acts as a client.

eventd

libcanberra	Enable plugin for sounds via media-libs/libcanberra
libnotify	Enable plugin to relay events to notification daemon (Note: not required for local notifications via net-misc/eventd)
notification	Enable plugin to display on-screen notifications
purple	Enable plugin for IM notifications via libpurple
webhook	Enable plugin to send payloads to webhook handlers
websocket	Enable support for WebSocket protocol

fatrat

bittorrent	Use the bittorrent protocol via net-libs/libtorrent-rasterbar.

freerdp

aad	Enable login via Azure AD
client	Build client binaries
fuse	Clipboard with FUSE file copy support
openh264	Enable H.264 support using media-libs/openh264
server	Build server binaries

frr

fpm	Enable Forwarding Plane Manager support
grpc	Enable gRPC plugin
nhrp	Build Next Hop Resolution Protocol daemon
ospfapi	Build OSPFAPI support
pam	Add support for PAM (via sys-libs/pam) to the Virtual Terminal Interface Shell (vtysh)
rpki	Enable RPKI

geckodriver

unchained	Apply the geckodriver-unchained patch, for Gecko-based non-Firefox browsers (e.g. Librewolf)

gerbera

curl	Support HTTP media sources (e.g. internet radio)
exiv2	Use media-gfx/exiv2 to extract EXIF information
ffmpegthumbnailer	Enable video thumbnail support with media-video/ffmpegthumbnailer
mysql	Use dev-db/mysql as backend rather than SQLite3
taglib	Use media-libs/taglib for reading files' metadata

gnome-remote-desktop

aac	Use media-libs/fdk-aac for audio output redirection of the RDP backend

gsasl

client	Build client component
gcrypt	Use dev-libs/libgcrypt for low-level crypto
ntlm	Add support for Microsoft's NTLM mechanism using net-libs/libntlm
server	Build server component

htbinit

esfq	Add support for Enhanced Stochastic Fairness queueing discipline.

hylafaxplus

html	Convert faxes into html email
jbig	JBIG Fax Compression Support
mgetty	Receive faxes via serial port connections
pam	hfaxd authentication via PAM

icaclient

hdx	Install and enable hdx-realtime-media-engine plugin
usb	Allow connecting USB devices to virtual desktops

icecast

kate	Add karaoke and text encapsulation support for Ogg files
yp	Build support for yp public directory listings

inetutils

dnsdomainname	Enable domainname
ftp	Enable ftp
ftpd	Enable ftpd
hostname	Enable hostname
ifconfig	Enable ifconfig
inetd	Enable inetd
logger	Enable logger
ping	Enable ping
ping6	Enable ping6
rcp	Enable rcp
rexec	Enable rexec
rexecd	Enable rexecd
rlogin	Enable rlogin
rlogind	Enable rlogind
rsh	Enable rsh
rshd	Enable rshd
syslogd	Enable syslogd
talkd	Enable talkd
telnet	Enable telnet
telnetd	Enable telnetd
tftp	Enable tftp
tftpd	Enable tftpd
traceroute	Enable traceroute
uucpd	Enable uucpd
whois	Enable whois

iputils

arping	Build and install arping -- tool for sending ARP requests to peers (see also net-analyzer/arping)
clockdiff	Build and install clockdiff -- tool for comparing clocks via ICMP packets
rarpd	Build and install rarpd -- server for handling RARP (reverse ARP) requests; generally only used by old systems
rdisc	Build and install rdisc -- server for the client side of the ICMP router discover protocol
tracepath	Build and install tracepath -- tool for tracing network paths for discovering MTU values

kafka-bin

connect	Install init for Kafka Connect Distributed mode
internal-zookeeper	Use bundled local zookeeper instance

kafkacat

avro	Enable avro serialization/deserialization support
json	Enable json support

kea

openssl	Use dev-libs/openssl instead of dev-libs/botan
samples	Install sample configuration files
shell	Install kea-shell text management client for Control Agent

knock

server	Installs the knockd server daemon.

libteam

zmq	Build witch net-libs/zeromq support

lldpd

cdp	Enable Cisco Discovery Protocol
dot1	Enable Dot1 extension (VLAN stuff)
dot3	Enable Dot3 extension (PHY stuff)
edp	Enable Extreme Discovery Protocol
fdp	Enable Foundry Discovery Protocol
graph	Create dot graphs in documentations
lldpmed	Enable LLDP-MED extension
old-kernel	Enable compatibility with Linux kernel older than 2.6.39
sanitizers	Enable code instrumentation with selected sanitizers
snmp	Enable the use of SNMP
sonmp	Enable SynOptics Network Management

memcached

slabs-reassign	Allow manual reassignment of memory slabs at the cost of slab optimizations.

minidlna

netgear	Enable netgear branding
readynas	Enable readynas branding

miniupnpd

igd2	Build for IGDv2 instead of an IGDv1
leasefile	Enable lease file.
nftables	Use net-firewall/nftables rather than net-firewall/iptables.
pcp-peer	Enable support for PCP-PEER to allow NAT-PMP clients to mangle their packets.
portinuse	Check if a port is in use before allowing a NAT-PMP client to map it.
strict	Be more strict regarding compliance with UPnP specifications.

modemmanager

mbim	Enable MBIM modem protocol
qmi	Enable support for the QMI modem protocol used by devices with Qualcomm chipsets
qrtr	Enable support for the QMI over IPC Router bus (QRTR) protocol

moonlight

cuda	Enable accelerated video rendering on NVIDIA hardware
embedded	Optimize UI for fullscreen non-desktop usage
glslow	Prefer direct KMS/DRM rendering over EGL/GLES rendering for better performance on some weaker GPUs
libdrm	Enable video rendering via x11-libs/libdrm
soundio	Enable sound output via media-libs/libsoundio instead of media-libs/libsdl2
vkslow	Prefer hardware YUV-RGB conversion and scaling over Vulkan for better performance on some weaker GPUs

mosh

client	Build network client
examples	Include example scripts
mosh-hardening	Enable compiler and linker options to frustrate memory corruption exploits
nettle	Use dev-libs/nettle for some cryptographic functions instead of dev-libs/openssl. With Nettle, some of mosh's own code is used for OCB.
server	Build network server
ufw	Install net-firewall/ufw rule set
utempter	Include libutempter support

mulk

checksum	Enable checksum verification for Metalink from dev-libs/openssl
metalink	Enable support for media-libs/libmetalink

netifrc

dhcp	Allow interfaces to configure via DHCP

netkit-bootparamd

libtirpc	Build against net-libs/libtirpc for RPC support

networkmanager

concheck	Enable connectivity checking support
connection-sharing	Support connection sharing (uses net-dns/dnsmasq)
dhclient	Use dhclient from net-misc/dhcp for getting an IP via DHCP
dhcpcd	Use net-misc/dhcpcd for getting an IP
elogind	Use sys-auth/elogind for session tracking
iptables	Use net-firewall/iptables for connection sharing
iwd	Use net-wireless/iwd instead of net-wireless/wpa_supplicant for wifi support by default
modemmanager	Enable support for mobile broadband devices using net-misc/modemmanager
nftables	Use net-firewall/nftables for connection sharing
nss	Use dev-libs/nss for cryptography
ofono	Use net-misc/ofono for telephony support.
ovs	Enable OpenVSwitch support
ppp	Enable support for mobile broadband and PPPoE connections using net-dialup/ppp
psl	Use public suffix list via net-libs/libpsl
resolvconf	Use net-dns/openresolv for managing DNS information in /etc/resolv.conf. Generally, a symlink to /run/NetworkManager/resolv.conf is simpler. On systems running systemd-resolved, disable this flag and create a symlink to /run/systemd/resolve/stub-resolv.conf.
teamd	Enable Teamd control support
tools	Build cli tools such as nmcli, nmtui and nm_cloud_setup
wext	Enable support for the deprecated Wext (Wireless Extensions) API; needed for some older drivers (e.g. ipw2200, ndiswrapper)
wifi	Enable support for wifi and 802.1x security

nextcloud-client

dolphin	Install the kde-apps/dolphin extension
nautilus	Install the gnome-base/nautilus extension
webengine	Enable old Flow1 login using dev-qt/qtwebengine

ntp

openntpd	Allow ntp to be installed alongside openntpd
parse-clocks	Add support for PARSE clocks
samba	Provide support for Samba's signing daemon (needed for Active Directory domain controllers)

ntpsec

arbiter	Arbiter 1088A/B GPS driver
early	Drop root privileges early
gdb	Enable debugging with gdb
generic	Enable support for generic time radios and GPSDOs
gpsd	Enable gpsd daemon support
heat	Install contrib heat generating scripts
hpgps	Hewlett Packard GPS driver
jjy	JJY driver
libbsd	Use libbsd instead of internal funcs
local	Support for undisciplined local clock (not recommended)
modem	NIST/USNO/PTB Modem Time Services
nist	Set local clock deps
nmea	NMEA GPS driver
ntpviz	Make visualizations of offsets, jiffies, etc.
oncore	Oncore driver
pps	PPS cesium clock driver
rclock_arbiter	Arbiter 1088A/B GPS driver
rclock_generic	Enable support for generic time radios and GPSDOs
rclock_gpsd	Enable gpsd daemon support
rclock_hpgps	Hewlett Packard GPS driver
rclock_jjy	JJY driver
rclock_local	Support for undisciplined local clock (not recommended)
rclock_modem	NIST/USNO/PTB Modem Time Services
rclock_nmea	NMEA GPS driver
rclock_oncore	Oncore driver
rclock_pps	PPS cesium clock driver
rclock_shm	Obtain refclock info from shared memory-segment
rclock_spectracom	Spectracom driver
rclock_trimble	Trimble driver
rclock_truetime	Trutime driver (deprecated)
rclock_zyfer	Zyfer driver
shm	Obtain refclock info from shared memory-segment
smear	Specify the interval over which a leap second is applied (experimental)
spectracom	Spectracom driver
trimble	Trimble driver
truetime	Trutime driver (deprecated)
zyfer	Zyfer driver

ofono

atmodem	ETSI AT modem support.
bluetooth	Enable Bluetooth modem support using net-wireless/bluez.
cdmamodem	Enable CDMA modem support.
datafiles	Enable install configuration and data files.
dundee	Enable BlueTooth DUN deamon support.
isimodem	Enable PhoNet/ISI modem support.
phonesim	Enable phone Simulator support
provision	Enable GPRS provisioning support
qmimodem	Enable Qualcomm QMI modem support
tools	Enable testing tools

oidentd

masquerade	Enable support for masqueraded/NAT connections

olsrd

pud	Install the Node Position Update plugin

openntpd

constraints	Enable HTTPS TLS time constraint support

openssh

ldns	Use LDNS for DNSSEC/SSHFP validation.
legacy-ciphers	Enable support for deprecated, soon-to-be-dropped DSA keys. See https://marc.info/?l=openssh-unix-dev>m=170494903207436>w=2.
livecd	Enable root password logins for live-cd environment.
security-key	Include builtin U2F/FIDO support
ssl	Enable additional crypto algorithms via OpenSSL
xmss	Enable XMSS post-quantum authentication algorithm

openssh-contrib

X509	Adds support for X.509 certificate authentication
hpn	Enable high performance ssh
ldns	Use LDNS for DNSSEC/SSHFP validation.
livecd	Enable root password logins for live-cd environment.
security-key	Include builtin U2F/FIDO support
ssl	Enable additional crypto algorithms via OpenSSL
xmss	Enable XMSS post-quantum authentication algorithm

openvswitch

monitor	Build the Python and GUI dependent monitor applications

owncloud-client

dolphin	Install the kde-apps/dolphin extension
nautilus	Install the gnome-base/nautilus extension

packETH

cli	Build and install packETHcli

plowshare

view-captcha	View captcha with aview

ps3mediaserver

multiuser	Allow renderer customization per-user.
transcode	Install optional dependencies for transcoding support via media-video/mplayer
tsmuxer	Install optional dependencies for transcoding support via media-video/tsmuxer

ptpd

debug	Enable debugging informations
experimental	Enable experimental features
ntp	Enable NTPD cooperation
pcap	Require net-libs/libpcap to allow layer 2 (raw Ethernet) transport
slave-only	Enable slave only operation (remove master mode functionality)
snmp	Require net-analyzer/net-snmp to enable SNMP configuration
statistics	Enable compution of statistics

putty

gssapi	Enable support for GSSAPI (virtual/krb5)
gtk	Build the PuTTY client which requires x11-libs/gtk+. If disabled only the CLI tools puttygen, plink, pscp and psftp will be built

r8125

multi-tx-q	Enable Multiple Tx Queue ("RSS" for sending)
ptp	Enable Precision Time Protocol support
rss	Enable Receive Side Scaling (RSS)
use-firmware	Support automatic firmware loading

r8152

center-tap-short	Enable support for center tap short

r8168

use-firmware	Enable support for automatic firmware loading

rdesktop

kerberos	Enable CredSPP support + Kerberos authentication
pcsc-lite	Enable smartcard support with sys-apps/pcsc-lite driver
xrandr	Enable XRandR window extension support

remmina

gvnc	Enable GVNC plugin using gtk-vnc, suitable for KVM and Vino servers
kwallet	Enable KDE Wallet plugin
spice	Support connecting to SPICE-enabled virtual machines
ssh	Enable support for SSH/SFTP protocol

rsync

rrsync	Install rrsync script to setup restricted rsync users via ssh logins
stunnel	Provide helper scripts for using rsync via >=net-misc/stunnel-4
system-zlib	Use system zlib instead of bundled one. This is incompatible with older rsync releases!
xxhash	Enable dev-libs/xxhash support for hashing

rygel

tracker	Install dependencies for the tracker plugin
transcode	Install dependencies for transcoding support

scponly

chroot	Enables adding and configuring an 'scponlyc' chrooted user
gftp	Enables gFTP compatibility
logging	Enables SFTP logging compatibility
passwd	Enables passwd compatibility
quota	Enables quota compatibility
rsync	Enables rsync compatibility with potential security risks
scp	Enables scp compatibility with potential security risks
sftp	Enables SFTP compatibility
subversion	Enables Subversion compatibility with potential security risks
unison	Enables Unison compatibility with potential security risks
wildcards	Enables wildcard processing with potential security risks
winscp	Enables WinSCP 2.0 compatibility with potential security risks

seafile-client

shibboleth	Build support for Shibboleth single sign-on

sipp

pcap	Enable functionality to replay RTP data from a pcap file

sitecopy

rsh	This allows the use of rsh (remote shell) and rcp (remote copy) for authoring websites. sftp is a much more secure protocol and is preferred.
webdav	Enable WebDav (Web-based Distributed Authoring and Versioning) support. This system allows users to collaborate on websites using a web based interface. See the ebuild for an FAQ page. Enables neon as well to handle webdav support.

sks

optimize	Enables bytecode optimization

smb4k

discovery	Build with net-libs/kdsoap-ws-discovery-client support to discover domains and workgroups

sntpd

adjtimex	Install adjtimex for the clock adjustment algorithm.

spice-gtk

gtk3	Build the spice client (spicy), requires x11-libs/gtk+:3
mjpeg	Enable builtin mjpeg video decoder
policykit	Enable sys-auth/polkit support for the usbredir acl helper
usbredir	Use sys-apps/usbredir to redirect USB devices to another machine over TCP
webdav	Support for folder-sharing between guest and client using net-libs/phodav

sshrc

mosh	Install Support for mosh

sslh

libev	Support event loops via dev-libs/libev

streamtuner

shout	Enable shoutcast plug-in.
xiph	Enable xiph.org plug-in.

stunnel

stunnel3	Install the stunnel3 wrapper.

sunshine

cuda	Enable accelerated video encoding on NVIDIA hardware
libdrm	Enable video encoding via x11-libs/libdrm
svt-av1	Enables software AV1 encoding via media-libs/svt-av1
trayicon	Enable system tray icon
x264	Enable software H.264 encoding via media-libs/x264
x265	Enable software HEVC encoding via media-libs/x265

tigervnc

dri3	Build with DRI3 support
drm	Build with DRM support
java	Build TigerVNC Java viewer
server	Build TigerVNC server
viewer	Build TigerVNC viewer

tinyssh

sodium	Use dev-libs/libsodium for cryptography

turbovnc

server	Build the server (vncserver, Xvnc)
viewer	Build the viewer (vncviewer)

uftp

server	Install uftp server daemon

vde

pcap	Enable the pcap-based plugin that allows creating a switch against a real interface.

wget

cookie-check	Enable cookie checks via net-libs/libpsl
libproxy	Support for automatic proxy configuration management through net-libs/libproxy.
metalink	Enable support for media-libs/libmetalink
ntlm	Enable support for NTLM (Windows-based) authorization
uuid	Generate UUIDs for the WARC (Web ARChive file format) using libuuid; otherwise use a simple RNG (random number generator)

wget2

gpgme	Build app-crypt/gpgme backend
openssl	Enable crypto support via dev-libs/openssl
psl	Use public suffix list via net-libs/libpsl

whois

xcrypt	Enable crypt through sys-libs/libxcrypt package

x2goserver

fuse	Use net-fs/sshfs to allow shared folders

xmrig

donate	Set the default donation level to 1% instead of 0
hwloc	Use sys-apps/hwloc for CPU affinity support

youtube-viewer

gtk	Install the gtk3 GUI

ytfzf

minimal	Skip all optional dependencies (may no longer work out-of-the-box and require custom setting up)
thumbnails	Pull media-gfx/ueberzugpp or media-gfx/ueberzug for viewing thumbnails (default method when using -t)

zerotier

sso	Enable support for Single sign-on through zeroidc

net-nds

389-ds-base

accountpolicy	Enable account policy plugin - automatically lock an account after a certain amount of time has elapsed
auto-dn-suffix	Enable auto bind with auto dn suffix over unix domain socket (LDAPI) support
autobind	Enable auto bind over unix domain socket (LDAPI) support
bitwise	Enable bitwise plugin - supported data in raw/bitwise format
dna	Enable dna (distributed numeric assignment ) plugin - to automatically assign unique uid numbers to new user entries as they are created.
ldapi	Enable LDAP over unix domain socket (LDAPI) support
pam-passthru	Enable pam-passthru plugin - for simple and fast system services used in ldap

ldapvi

gnutls	Use net-libs/gnutls instead of dev-libs/openssl

nsscache

nsscache	Depend on sys-auth/libnss-cache to handle flat files
s3	Support for S3-based NSS sources

openldap

argon2	Enable password hashing algorithm from app-crypt/argon2
autoca	Automatic Certificate Authority overlay
cleartext	Enable use of cleartext passwords
experimental	Enable experimental backend options
kinit	Enable support for kerberos init
minimal	Build libraries & userspace tools only. Does not install any server code
odbc	Enable ODBC and SQL backend options
overlays	Enable contributed OpenLDAP overlays
pbkdf2	Enable support for pbkdf2 passwords
sha2	Enable support for pw-sha2 password hashes
smbkrb5passwd	Enable overlay for syncing ldap, unix and lanman passwords

rpcbind

remotecalls	Enable remote calls
warmstarts	Enables rpcbind to cache configuration for warm restarts

net-news

rssguard

libmpv	Enable media player support via libmpv from media-video/mpv
qtmultimedia	Enable media player support via dev-qt/qtmultimedia
webengine	Use dev-qt/qtwebengine for embedded web browser

sfeed

theme-mono	Use mono theme
theme-mono-highlight	Use mono_highlight theme
theme-newsboat	Use newsboat theme
theme-templeos	Use templeos theme

net-nntp

nzbget

parcheck	Enable support for checking PAR archives

slrn

canlock	Add support for cancel locks via net-libs/canlock
uudeview	Add support for yEnc coding and more using dev-libs/uulib

tin

cancel-locks	Enable Cancel-Lock header functionality
gpg	Enable app-crypt/gnupg support
libtls	Prefer dev-libs/libretls as SSL/TLS provider (ineffective with USE=-ssl)

net-p2p

airdcpp-webclient

nat-pmp	Enable support for the NAT-PMP protocol
tbb	Enable support of the TBB library to improve performance
webui	Enable the Web UI

amule

daemon	Enable amule daemon
remote	Enable remote controlling of the client
stats	Enable statistic reporting

bitcoin-core

berkdb	Support legacy wallets in Berkeley DB format
bitcoin-cli	Build and install bitcoin-cli command line interface
cli	Build and install bitcoin-cli command line interface
daemon	Build and install bitcoind daemon
external-signer	Include support for external wallet signer programs
gui	Build and install Bitcoin-Qt GUI
libs	Build and install libbitcoinconsensus
nat-pmp	Enable NAT-PMP port forwarding
qrcode	Enable generation of QR Codes for receiving payments
sqlite	Support descriptor wallets in SQLite format
system-leveldb	Link with virtual/bitcoin-leveldb rather than embedding an internal copy
system-libsecp256k1	Link with dev-libs/libsecp256k1 rather than embedding an internal copy
systemtap	Enable SystemTap/DTrace tracing
test-full	Run tests that take a long time
upnp	Enable Universal Plug and Play
zeromq	Report blocks and transactions via zeromq

bitcoin-qt

external-signer	Include support for external wallet signer programs
nat-pmp	Enable NAT-PMP port forwarding
qrcode	Enable generation of QR Codes for receiving payments
systemtap	Enable SystemTap/DTrace tracing
upnp	Enable Universal Plug and Play
wallet	Enable wallet support
zeromq	Report blocks and transactions via zeromq

bitcoind

external-signer	Include support for external wallet signer programs
nat-pmp	Enable NAT-PMP port forwarding
systemtap	Enable SystemTap/DTrace tracing
upnp	Enable Universal Plug and Play
wallet	Enable wallet support
zeromq	Report blocks and transactions via zeromq

dbhub

switch-user	Enable support for switching user

deluge

console	Enable default console UI
webinterface	Install dependencies needed for the web interface

eiskaltdcpp

cli	Enable sample cli based on readline
daemon	Enable eiskaltdcpp-daemon
dht	Enable DHT (distributed hash table) support for libeiskaltdcpp
libcanberra	Enable sound notifications support over libcanberra in EiskaltDC++ Gtk
minimal	Don't install headers

fms

frost	Add support for frost boards
ssl	Add support for FCP connection over SSL

freenet

nss	Use nss for crypto operations, if it is the fastest way

go-ethereum

devtools	Build Ethereum development tools (evm, abigen, puppeth, ...)

ktorrent

bwscheduler	Schedule upload and download limits over a period of a week
downloadorder	Specify the download order of a multi-file torrent
infowidget	Displays general information about a torrent in several tabs
ipfilter	Filter IP addresses through a blocklist
logviewer	Displays the logging output
magnetgenerator	Generates magnet URI's
mediaplayer	Phonon-based media player
rss	Syndication plugin for KTorrent, supporting RSS and Atom feeds
scanfolder	Scan folders for torrent files and load them
shutdown	Shutdown when done
stats	Shows statistics about torrents in several graphs
upnp	Forward ports using UPnP
webengine	Embedded search for torrents using dev-qt/qtwebengine
zeroconf	Discover peers on the local network using the Zeroconf protocol

mldonkey

bittorrent	enable bittorrent support
fasttrack	enable fasttrack support
gnutella	enable gnutella and gnutella2 support

qbittorrent

webui	Install qBittorrent Web UI (qbittorrent-nox) and systemd/OpenRC service

retroshare

cli	Enables terminal login support for retroshare-service
jsonapi	Enables the new RetroShare JSON API
libupnp	Enables UPnP port forwarding via net-libs/libupnp
miniupnp	Enables UPnP port forwarding via net-libs/miniupnpc
plugins	Enables plugin support
service	Enables the new RetroShare service
sqlcipher	Enables GXS database encryption via SQLCipher

syncthing

tools	Install stdiscosrv, strelaysrv and other tools to /usr/libexec/syncthing/.

transmission

cli	Build command-line client
debug	Enable assertions
mbedtls	Use mbed TLS instead of OpenSSL

transmission-remote-gtk

libproxy	Use net-libs/libproxy for getting the HTTP/HTTPS/SOCKS proxy configuration.

net-print

cups

openssl	Use dev-libs/openssl instead of net-libs/gnutls for TLS support

cups-filters

foomatic	Build the included foomatic-rip printer driver. Strongly recommended.
pclm	Enable PCLm support

cups-meta

browsed	Include support for the cups-browsed daemon.
foomatic	Include support for the foomatic-rip printer driver. Strongly recommended.
poppler	Include support for the app-text/poppler filters.

dymo-cups-drivers

usb-modeswitch	Include usb_modeswitch for some hardware (bug #601242)

fax4cups

efax	Install net-misc/efax backend
hylafax	Install net-misc/hylafax backend
mgetty-fax	Install net-dialup/mgetty backend

hplip

X	Enables scanner GUI dependencies with USE="scanner" where media-gfx/xsane is preferred over media-gfx/sane-frontends
fax	Enable fax on multifunction devices which support it
hpcups	Build the hpcups driver for cups (by HP)
hpijs	Build the IJS driver for cups (Foomatic)
kde	Enables kde-misc/skanlite as scanner GUI with USE="scanner X"
libusb0	Depend on virtual/libusb SLOT 0. Some old printers do not work with virtual/libusb SLOT 1.
minimal	Only build internal hpijs/hpcups driver (not recommended at all, make sure you know what you are doing)
parport	Enable parallel port for devices which require it
scanner	Enable scanner on multifunction devices which support it
snmp	Add support for net-analyzer/net-snmp which enables this driver to work over networks (both for server and client)
static-ppds	Use statically-generated PPDs instead of Dynamic PPDs. Although this is deprecated some printers may still need it to work properly. Use this flag if hp-setup fails to find/create a valid PPD file

hplip-plugin

orblite	Install the ORBlite scanner plugin

kyocera-1x2x-mfp-driver

rastertokpsl-fix	Use custom wrapper script to sanitize arguments before passing to 'rastertokpsl' filter program

libcupsfilters

poppler	Build the pdftoraster filter

libppd

poppler	Use the app-text/poppler pdftops filter

net-proxy

haproxy

51degrees	Device Detection using 51 Degrees
net_ns	Enable network namespace support (CONFIG_NET_NS)
pcre-jit	Use JIT support for PCRE
prometheus-exporter	Also build the prometheus exporter
slz	Use dev-libs/libslz compression library
tools	Install additional tools (halog, iprange)
wurfl	Device Detection using WURFL

privoxy

brotli	Decompress brotli compressed data using app-arch/brotli before filtering
client-tags	Enable support for client-specific tags
compression	Allow privoxy to compress buffered content before sending to the client, if it supports it
editor	Enable the web-based actions file editor
extended-host-patterns	Enable and require PCRE syntax in host patterns. You must convert action files to PCRE, see privoxy-url-pattern-translator.pl (see tools USE flag). Use at your own risk!
extended-statistics	Gather extended statistics
external-filters	Allow to filter content with scripts and programs. Experimental
fast-redirects	Support fast redirects
force	Allow single-page disable (force load)
fuzz	Exposes Privoxy internals to input from files or stdout. Intended for fuzzing testing
graceful-termination	Allow to shutdown Privoxy through the webinterface
image-blocking	Allows the +handle-as-image action, to send "blocked" images instead of HTML
jit	Enable PCRE jit (recommended)
lfs	Support large files (>2GB) on 32-bit systems
mbedtls	Use net-libs/mbedtls for HTTPS filtering
openssl	Use dev-libs/openssl for HTTPS filtering
png-images	Use PNG format instead of GIF for built-in images
sanitize	Enable asan, msan and usan sanitizers. Your compiler must support them
ssl	HTTPS inspection support. Enables privoxy to perform SSL MITM filtering, see docs, use with care
stats	Keep statistics
threads	Enable POSIX threads. Highly recommended, otherwise both build and run-time features may not work properly.
toggle	Support temporary disable toggle via web interface
tools	Install log parser, regression tester and user agent generator tools
whitelists	Support trust files (white lists)
zlib	Decompress zlib compressed data using sys-libs/zlib before filtering

rejik

banlists	Install upstream provided simple banlists

squid

ecap	Adds support for loadable content adaptation modules (http://www.e-cap.org)
esi	Enable ESI for accelerators, will cause squid reverse proxies to be capable of the Edge Acceleration Specification (www.esi.org)
htcp	Enable HTCP protocol
logrotate	Use app-admin/logrotate for rotating logs
qos	Adds support for Quality of Service using netfilter conntrack - see qos_flow directive for more info
ssl-crtd	Adds support for dynamic SSL certificate generation in SslBump environments
tproxy	Enables real Transparent Proxy support for Linux Netfilter TPROXY
wccp	Enable Web Cache Coordination Protocol
wccpv2	Enable Web Cache Coordination V2 Protocol

tinyproxy

filter-proxy	Enable filtering of domains/URLS
reverse-proxy	Enable reverse proxying
transparent-proxy	Enable transparent proxying
upstream-proxy	Enable upstream proxying
xtinyproxy-header	Include the X-Tinyproxy header

trojan

mysql	build with MySQL support
nat	Build with NAT support
reuseport	Build with SO_REUSEPORT support
tcpfastopen	Force build with TCP Fast Open support

tsocks

dns	Force DNS queries to use SOCKS server via tcp
envconf	Allow TSOCKS_CONF_FILE to specify configuration file
server-lookups	Allow hostname resolution _for_ SOCKS servers
tordns	Apply tordns patch which allows transparent TORification of the DNS queries

net-voip

mumble

g15	Enable support for the Logitech G15 LCD (and compatible devices).
pipewire	Enable pipewire support for audio output.
rnnoise	Enable alternative noise suppression option based on RNNoise.

murmur

ice	Use dev-libs/Ice to enable remote control capabilities.

umurmur

mbedtls	Use net-libs/mbedtls as TLS provider
shm	Enable shared memory support

yate

amrnb	use AMR-NB
dahdi	Enable Dahdi driver
gsm	use GSM codec
ilbc	Enable iLBC codec
ilbc-webrtc	Enable iLBC webrtc codec
isac-fixed	Enable iSAC fixed codec
isac-float	Enable iSAC float codec
mysql	use MySQL client library
postgres	use Postgress SQL
spandsp	use spandsp library
speex	use Speex codec
tdmcard	Enable TDMV API card driver
wanpipe	Enable Wanpipe support
wpcard	Enable Wanpipe card driver
zaptel	Enable Zaptel driver

net-vpn

eduvpn-common

openvpn	enable support for OpenVPN
wireguard	enable support for WireGuard

frp

client	Build and install frp client (frpc)
server	Build and install frp server (frps)

libreswan

dnssec	Use DNSSEC resolver (requires net-dns/unbound)
ikev1	Enable the IKEv1 protocol

networkmanager-sstp

gtk4	Use gui-libs/gtk for GUI support.

networkmanager-strongswan

gtk4	Use GTK4 instead of GTK3.

ocserv

otp	Enable support for one-time passwords

openconnect

gssapi	Build GSSAPI support
libproxy	Enable proxy support
pskc	Enable PSKC file storage of HOTP/TOTP keys
stoken	Enable stoken support

openvpn

dco	Enable support for kernel data channel offload
down-root	Enable the down-root plugin
iproute2	Enabled iproute2 support instead of net-tools
mbedtls	Use mbed TLS as the backend crypto library
openssl	Use OpenSSL as the backend crypto library
pkcs11	Enable PKCS#11 smartcard support
plugins	Enable the OpenVPN plugin system

ovpn-dco

debug	Enable debug output in dmesg

pptpd

gre-extreme-debug	Log all GRE accepted packets when in debug mode (required if you want upstream support)

strongswan

constraints	Enable advanced X.509 constraint checking plugin
dhcp	Enable server support for querying virtual IP addresses for clients from a DHCP server. (IKEv2 only)
eap	Enable support for the different EAP modules that are supported
farp	Enable faking of ARP responses for virtual IP addresses assigned to clients (IKEv2 only)
gcrypt	Enable dev-libs/libgcrypt plugin which provides 3DES, AES, Blowfish, Camellia, CAST, DES, Serpent and Twofish ciphers along with MD4, MD5 and SHA1/2 hash algorithms, RSA and DH groups 1,2,5,14-18 and 22-24(4.4+). Also includes a software random number generator.
non-root	Force IKEv1/IKEv2 daemons to normal user privileges. This might impose some restrictions mainly to the IKEv1 daemon. Disable only if you really require superuser privileges.
openssl	Enable dev-libs/openssl plugin which is required for Elliptic Curve Cryptography (DH groups 19-21,25,26) and ECDSA. Also provides 3DES, AES, Blowfish, Camellia, CAST, DES, IDEA and RC5 ciphers along with MD2, MD4, MD5 and SHA1/2 hash algorithms, RSA and DH groups 1,2,5,14-18 and 22-24(4.4+) dev-libs/openssl has to be compiled with USE="-bindist".
pkcs11	Enable pkcs11 support
strongswan_plugins_addrblock	Enable support for the addrblock crypto plugin
strongswan_plugins_aesni	Enable support for Intel AES-NI crypto plugin
strongswan_plugins_blowfish	Enable support for the blowfish plugin
strongswan_plugins_bypass-lan	Enable support for the bypass-lan plugin
strongswan_plugins_ccm	Enable support for the ccm plugin
strongswan_plugins_chapoly	Enable ChaCha20/Poly1305 AEAD implementation and ChaCha20 XOF plugin
strongswan_plugins_ctr	Enable support for the ctr plugin
strongswan_plugins_error-notify	Enable support for the error-notify plugin
strongswan_plugins_forecast	Enable multicast and broadcast forwarding plugin
strongswan_plugins_gcm	Enable support for the gcm plugin
strongswan_plugins_ha	Enable support for the ha plugin
strongswan_plugins_ipseckey	Enable support for the ipseckey plugin
strongswan_plugins_kdf	Enable support for the kdf plugin
strongswan_plugins_led	Enable support for the led plugin
strongswan_plugins_lookip	Enable support for the lookip plugin
strongswan_plugins_newhope	Enable plugin that allows key exchange based on post-quantum computer New Hope algorithm
strongswan_plugins_ntru	Enable support for the ntru plugin
strongswan_plugins_padlock	Enable support for the padlock plugin
strongswan_plugins_rdrand	Enable support for the rdrand plugin
strongswan_plugins_save-keys	Enable plugin that saves IKE and/or ESP keys to files compatible with Wireshark (for debugging)
strongswan_plugins_systime-fix	Enable support for the systime-fix plugin
strongswan_plugins_unbound	Enable support for the unbound plugin
strongswan_plugins_unity	Enable support for the unity plugin
strongswan_plugins_vici	Enable support for the vici plugin
strongswan_plugins_whitelist	Enable support for the whitelist plugin
strongswan_plugins_xauth-noauth	Enable support for the xauth-noauth plugin

tinc

uml	Enable support for User Mode Linux Sockets
vde	Enable Virtual Distributed Ethernet (VDE) based networking

tor

scrypt	Use app-crypt/libscrypt for the scrypt algorithm
server	Enable tor's relay module so it can operate as a relay/bridge/authority
tor-hardening	Compile tor with hardening on vanilla compilers/linkers

vpnc

resolvconf	Enable support for DNS managing framework net-dns/openresolv

wireguard-modules

debug	Enable verbose debug reporting in dmesg of various WireGuard peer and device information.
module	Compile the actual WireGuard kernel module. Most certainly you want this enabled, unless you're doing something strange.
module-src	Install the module source code to /usr/src, in case you like building kernel modules yourself.

wireguard-tools

wg-quick	Install the wg-quick(8) helper tool. Most users want to use this.

net-wireless

aic8800

firmware	Install device firmware

aircrack-ng

airdrop-ng	Build airdrop-ng
airgraph-ng	Build airgraph-ng
experimental	Build the "experimental" tools which may randomly fail to run properly
netlink	Use netlink for channel control instead of WEXT

bladerf

tecla	use libtecla for command line editing, tab completion, and history

bladerf-fpga

x115	bitstream for the x115 kLE Cyclone IV FPGA bladerf model"
x40	bitstream for the x40 kLE Cyclone IV FPGA bladerf model"
xA4	bitstream for the xA4 49 kLE Cyclone V FPGA bladerf 2.0 micro model"
xA9	bitstream for the xA9 301 kLE Cyclone V FPGA bladerf 2.0 micro model"

blueman

network	Add functionality to setup (host) PAN connections using either net-dns/dnsmasq or net-misc/dhcp

bluez

btpclient	Enable BTP client
deprecated	Build deprecated plugins
experimental	Build experimental plugins
extra-tools	Install tools that upstream doesn't install on purpose by default. All this tools shouldn't be used. Then, please notify upstream about you still need them to let them know the situation.
mesh	Add support for Bluetooth Mesh control application and advertising bearer.
midi	Enable MIDI support
obex	Enable OBEX transfer support
test-programs	Install tools for testing of various Bluetooth functions

dump1090

bladerf	Build with Nuand BladeRF support
hackrf	Build with Great Scott Gadgets HackRF support
minimal	Exclude all HTML/webserver extras for a tiny build, e.g. to export data only
rtlsdr	Build with Realtek RTL2832U (rtlsdr) support

gnome-bluetooth

sendto	Build the bluetooth-sendto application to send files to various locations/devices

gnuradio

analog	enable analog signal processing blocks
audio	enable blocks to connect to audio sources (mic-in) and sinks (speaker-out) ports on a computer
channels	enable channel mode blocks
ctrlport	enable control port interface
digital	enable digital signal processing blocks
dtv	enable digital tv signal processing blocks
fec	enable block for convolutional encoding using the CCSDS standard polynomial ("Voyager")
filter	enable filter signal processing blocks
grc	enable GNU Radio Companion graphical tool to design signal processing flow graphs
iio	enable enable support for IIO devices
modtool	enable modtool for editing GNU Radio modules and components
network	enable block for networking support
performance-counters	enable block performance counters
soapy	enable support for SoapySDR blocks
trellis	enable trellis blocks for FSM
uhd	install UHD source and sink blocks
utils	install scripts to enable viewing and analysis of files produced by flow graphs
vocoder	enable blocks for audio voice encoders
wavelet	enable wavelet signal processing blocks
zeromq	enable zeromq message passing blocks

gqrx

gr-audio	Use audio support from net-wireless/gnuradio

gr-osmosdr

airspy	Build with Airspy support through net-wireless/airspy
bladerf	Build with Nuand BladeRF support through net-wireless/bladerf
hackrf	Build with Great Scott Gadgets HackRF support through net-libs/libhackrf
iqbalance	Enable support for I/Q balancing using gr-iqbal through net-wireless/gr-iqbal
rtlsdr	Build with Realtek RTL2832U support through net-wireless/rtl-sdr
sdrplay	Enable support for SDRplay devices through net-wireless/sdrplay
soapy	Build with SoapySDR support through net-wireless/soapysdr
uhd	Build with Ettus Research USRP Hardware Driver support through net-wireless/uhd
xtrx	Build with xtrx Hardware Driver support through net-wireless/libxtrx

horst

pcap	Add support for network packet capture via net-libs/libpcap

hostapd

internal-tls	Use internal TLSv1 implementation instead of depending on OpenSSL or GnuTLS
netlink	Adding support for using netlink to create VLANs
suiteb	Adding support for NSA Suite B Cryptography
wps	Add support for Wi-Fi Protected Setup

iwd

client	Enable iwctl client tool
monitor	Enable iwmon monitor tool
ofono	Enable support for oFono SIM authentication
standalone	Enable standalone mode with built-in DHCP client and DNS handling"
systemd	Use systemd-resolve rather than resolvconf for DNS handling in standalone mode
wired	Enable ethernet authentication daemon

kismet

libusb	Support libusb based capture sources such as mousejack, cc2540(ble), and nrf51822(ble)
mqtt	Enable MQTT support
pcre	Build with pcre support
rtlsdr	Enable rtlsdr based kismet capture sources
suid	Install a setuid root helper binary with limited functionality; this allows running kismet as a normal user, significantly reducing security risks
ubertooth	Enable capture source for ubertooth to sniff bluetooth low energy
wext	Enable building kismet with support for the deprecated Linux Wireless Extensions. This is required for some out of tree and staging drivers, and kismet has not been well tested with it disabled, so it defaults to on.

libxtrxll

usb3380	support xtrx usb model

neard

tools	Build and install 'nfctool' for further NFC debugging

rtl-sdr

zerocopy	may cause a bus error on some ARM systems

rtl_433

rtlsdr	Build with Realtek RTL2832U (rtlsdr) support
soapysdr	Build with SoapySDR support

soapysdr

bladerf	Add support for bladerf hardware
hackrf	Add support for hackrf hardware
plutosdr	Add support for Analog Devices ADALM-PLUTO hardware
rtlsdr	Add support for rtlsdr hardware
uhd	Add support for Ettus USRP hardware

ubertooth

bluez	use bluez to support clock following and scanning
ubertooth1-firmware	Build/install ubertooth1-firmware

uhd

b100	support B100 hardware
b200	support B200, B210, B200mini, B205mini hardware
e300	support E300, E310 hardware
mpmd	support N300, N310 hardware
octoclock	Octoclock Network Support
usrp1	support USRP1 hardware
usrp2	support USRP2, N200, N210 hardware
utils	utilities needed to list, query, calibrate, or update FPGA/Firmware
x300	support X300, X310 hardware

unifi

system-mongodb	Using dev-db/mongodb systemd service instead of the bundled one

urh

airspy	use native backend which directly uses net-wireless/airspy
audio	use a soundcard instead of an sdr
bladerf	use native backend which directly uses net-wireless/bladerf
hackrf	use native backend which directly uses net-libs/libhackrf
limesdr	use native backend which directly uses net-wireless/limesuite
plutosdr	use native backend which directly uses net-libs/libiio
rtlsdr	use native backend which directly uses net-wireless/rtl-sdr
sdrplay	use native backend which directly uses net-wireless/sdrplay
uhd	use native backend which directly uses net-wireless/uhd

wepattack

john	Build with app-crypt/johntheripper support

wireless-tools

multicall	Build the most commonly used tools as one binary

wpa_supplicant

ap	Add support for access point mode
broadcom-sta	Flag to help users disable features not supported by broadcom-sta driver
eap-sim	Add support for EAP-SIM authentication algorithm
eapol-test	Build and install eapol_test binary
fasteap	Add support for FAST-EAP authentication algorithm
fils	Add support for Fast Initial Link Setup (802.11ai)
hs2-0	Add support for 802.11u and Passpoint for HotSpot 2.0
macsec	Add support for wired macsec
mbo	Add support Multiband Operation
mesh	Add support for mesh mode
p2p	Add support for Wi-Fi Direct mode
privsep	Enable wpa_priv privledge separation binary
ps3	Add support for ps3 hypervisor driven gelic wifi
smartcard	Add support for smartcards
tdls	Add support for Tunneled Direct Link Setup (802.11z)
tkip	Add support for WPA TKIP (deprecated due to security flaws in 2009)
uncommon-eap-types	Add support for GPSK, SAKE, GPSK_SHA256, IKEV2 and EKE
wep	Add support for Wired Equivalent Privacy (deprecated due to security flaws in 2004)
wimax	Add support for Wimax EAP-PEER authentication algorithm
wps	Add support for Wi-Fi Protected Setup

sci-astronomy

cpl

gasgano	Enable support for sci-astronomy/gasgano file organizer

kstars

password	Store passwords securely via dev-libs/qtkeychain
wcs	Enable support for World Coordinate System library using wcslib

psfex

plplot	Build with sci-libs/plplot to allow diagnostic plots during processing

scamp

plplot	Build with sci-libs/plplot to allow diagnostic plots during processing

sextractor

modelfit	Enable profile model fitting, needs sci-libs/atlas and sci-libs/fftw

siril

libconfig	Require dev-libs/libconfig to read old configuration files
wcs	Add supprt astrometry features using sci-astronomy/wcslib

stellarium

deep-sky	Install extra deep sky objects catalog (may affect performance)
lens-distortion	Enable lens distortion estimator plugin
libcxx	Use external libraries for STL features not available in libc++
media	Enable sound and video support
scripting	Enable JS scripting via dev-qt/qtscript in Qt5 or using Qml via dev-qt/qtdeclarative in Qt6
show-my-sky	Enable a better atmosphere model via sci-astronomy/calcmysky
stars	Install extra star catalogs
telescope	Enable telescope control via sci-libs/indilib
webengine	Show online results about the selected star in an embedded window using dev-qt/qtwebengine
xlsx	Support XLSX (Excel) files via dev-libs/qxlsx

swarp

cfitsio	Link with sci-libs/cfitsio

wcslib

fits	Enable support for the FITS format through sci-libs/cfitsio
pgplot	Builds PGBSOX routines, needs sci-libs/pgplot library
tools	Builds and installs extra command line utilities for WCS checking

sci-biology

abyss

misc-haskell	build abyss-samtobreak tool, pull in haskell toolchain

bioperl

db	Install sci-biology/bioperl-run
network	Install sci-biology/bioperl-run
run	Install sci-biology/bioperl-run

clustalw-mpi

mpi-njtree	Use MPI (as opposed to serial) code for computing neighbor-joining trees
static-pairalign	Use static (as opposed to dynamic) scheduling for pair alignments

exonerate

utils	Install the follow binaries: esd2esi, fasta2esd, fastaannotatecdna, fastachecksum, fastaclean, fastaclip, fastacomposition, fastadiff, fastaexplode, fastafetch, fastahardmask, fastaindex, fastalength, fastanrdb, fastaoverlap, fastareformat, fastaremove, fastarevcomp, fastasoftmask, fastasort, fastasplit, fastasubseq, fastatranslate, fastavalidcds

fasttree

double-precision	use double precision instead of single-precision floating point (2x memroy required)

mcl

blast	Add support for NCBI BLAST data

mothur

boost	Depend on dev-libs/boost for make.contigs to read .gz compressed files.
gsl	Use sci-libs/gsl to support diversity estimates for estimiator.single.
hdf5	Support Biom format 2.0 for the biom.info command via sci-libs/hdf5.

newick-utils

xml	Uses dev-libs/libxml2 to handle ornaments

ucsc-genome-browser

server	Install genome browser Web application. If this flag is off, only libraries and utilities from the suite are installed.

yass

dmalloc	Enable debugging with the dmalloc library
lowmem	Build for environments with low amounts of memory

sci-calculators

datamash

linux-crypto	Use Linux kernel cryptographic API
openssl	Use dev-libs/openssl for hash routines instead of internal gnulib

units

units-cur	Install the units_cur python script that updates currencies

sci-chemistry

avogadro2

rpc	Enable RPC server
vtk	include vtk support

chemtool

emf	EMF export support

gnome-chemistry-utils

gnumeric	Add a Gnumeric plugin to provide a molarmass function for the spreadsheet

gromacs

build-manual	Build manual instead of downloading it
clang	Build gromacs with Clang instead of default compiler
clang-cuda	Use clang for cuda units compilation
cuda	Enable cuda non-bonded kernels
double-precision	More precise calculations at the expense of speed
gmxapi	Add support for gmxapi library
gmxapi-legacy	Enable installing lagacy headers
hwloc	Enable HWLoc lib support
lmfit	Use external sci-libs/lmfit
mkl	Use sci-libs/mkl for fft, blas, lapack routines
nnpot	Allow to use sci-libs/caffe2 for NN Potentials
offensive	Enable gromacs partly offensive quotes
opencl	Enable opencl non-bonded kernels
single-precision	Single precision version of gromacs (default)
tng	Enable new trajectory format - tng

molequeue

client	Build the client application
server	Build the serve application
zeromq	Build with net-libs/zeromq support

openbabel

inchi	Build support for IUPAC International Chemical Identifier format
json	Build support for JSON formats (ChemDoodle, PubChem, etc...)

pymol

web	Install Pymodule needed for web app support

raster3d

gd	libgd support for PNG and JPEG output

vmd

gromacs	Add support for TNG file format
msms	Add support for MSMS SES calcualtion tool
povray	Add support for povray raytracer for HQ images
tachyon	Add support for tachyon raytracer for HQ images

votca

gromacs	Add support for gromacs file formats through sci-chemistry/gromacs

sci-electronics

gerbv

unit-mm	Set default unit for coordinates in status bar to mm

ghdl

llvm	Build LLVM code generator

gtkwave

fasttree	Enables experimental Fast SST Tree widget code.
fatlines	Renders lines as double width in gtkwave.
judy	Enables Judy array support.
packed	Enables '#pragma pack' for data arrays (saves memory, costs time).

kicad-meta

minimal	Do not install extra data like 3D packages and templates.

ktechlab

gpsim	Enable support for Microchip PIC microcontrollers similation using dev-embedded/gpsim

librepcb

opencascade	Build with sci-libs/opencascadethe 3D features (e.g. reading/writing STEP files)

ngspice

deprecated	Build old and deprecated apps
shared	Build ngspice as a shared library

nvc

llvm	Build LLVM code generator

pcb

gcode	gcode file export
gif	GIF graphics export
gsvit	GSvit file export
jpeg	JPEG graphics export
m4lib-png	Enable creating png previews for the m4 library
nelma	NELMA file export
png	PNG graphics export
tk	Build tcl/tk graphical QFP footprint generator
toporouter	Build toporouter

pulseview

decode	Enable decoding of protocols while capturing

sigrok-cli

decode	Enable decoding of protocols while capturing

splat

hires	Builds additional high resolution application 'rfsplat-hd'

sci-geosciences

gmt

gdal	Enable sci-libs/gdal library support
geos	Enable sci-libs/geos library support
gmttria	Non GNU triangulation method, more efficient

gpsd

dbus	export gpsd data over dbus connections
latency-timing	support latency timing information
ntp	Enable net-misc/ntp shared memory interface and PPS kernel support for GPS time
shm	export gpsd over shared memory
sockets	export gpsd over unix sockets

grass

geos	Use sci-libs/geos for v.buffer and adds extended options to the v.select module
las	Include support for LAS and LAZ encoded LiDAR files through sci-geosciences/liblas
pdal	Enable support for PDAL for point clouds via sci-libs/pdal
svm	Enable support for the Support Vector Machine library sci-libs/libsvm

gshhs

data	Add earth data with sci-geosciences/gshhs-data

liblas

gdal	Add support for the sci-libs/gdal geospatial raster library

mapserver

apache	Enable mapserver to run under apache
geos	Enable sci-libs/geos library support
postgis	Enable dev-db/postgis support

merkaartor

libproxy	Use net-libs/libproxy for getting the HTTP/HTTPS/SOCKS proxy configuration
webengine	Enable dev-qt/qtwebengine in some plugins
zbar	Enable barcode support in MWalkingPapersBackground/GeoImage via media-gfx/zbar

owntracks-recorder

crypt	Enable support for payload encryption with dev-libs/libsodium
http	Enable support for the built-in HTTP REST API
kill	Enable support removing data via the API (dangerous)
lua	Enable support for Lua hook integration
mqtt	Enable MQTT support
ping	Enable support for the "pingping" monitoring feature
tours	Enable recorder support for shared views

qgis

3d	Build QGIS 3D library using dev-qt/qt3d
georeferencer	Determines whether georeferencer plugin should be built
grass	Add support for grass
hdf5	Enable MDAL support for sci-libs/hdf5
mapserver	Determines whether mapserver should be built
netcdf	Enable MDAL support for GRIB and XMDF formats
pdal	Enable support for PDAL for point clouds via sci-libs/pdal
qml	Enable support Qml-based plugins using dev-qt/qtdeclarative
webengine	Enable webengine support using dev-qt/qtwebengine

viking

geoclue	Use app-misc/geoclue to determine current location
libexif	Use media-libs/libexif for EXIF support
oauth	Enable OAuth authentication for OSM

sci-libs

ViSP

coin	Enables Coin3D support.
demos	Installs demo programs.
dmtx	Enables barcode data matrix support.
ogre	Enables dev-games/ogre support.
opencv	Enables media-libs/opencv support.
pcl	Enables sci-libs/pcl support.
tutorials	Installs tutorials.
zbar	Enables barcodes reading.

XNNPACK

assembly	Build with assembly micro-kernels
jit	Build with JIT micro-kernels
memopt	Build with optimized memory allocation scheme
sparse	Build with graph rewriting for sparse inference

adolc

boost	Use the boost allocator from dev-libs/boost
sparse	Add support for sparse matrix algebra with sci-libs/colpack

armadillo

arpack	Link with sci-libs/arpack libraries for eigen decomposition
mkl	Use matrix allocation from the Intel MKL sci-libs/mkl
superlu	Use SuperLU for sparse linear equation solving sci-libs/superlu

arprec

qd	Use sci-libs/qd for quad-double datatype

atlas

generic	Build atlas assuming a fairly generic architecture (sse2 for x86, core2 for amd64)

avogadrolibs

archive	Enable archive support using app-arch/libarchive
vtk	Enable sci-libs/vtk support

blis

64bit-index	Enable 64bit array indexing, incompatible with runtime switching
eselect-ldso	Enable runtime library switching by eselect and ld.so.
openmp	Use openmp threadding model
pthread	Use pthread threadding model
serial	Use no threadding model

caffe2

distributed	Support distributed applications
fbgemm	Use FBGEMM
flash	Enable flash attention
gloo	Use sci-libs/gloo
mkl	Use sci-libs/mkl for blas, lapack and sparse blas routines
nnpack	Use NNPACK
numpy	Add support for math operations through numpy
onednn	Use oneDNN
openblas	Use sci-libs/openblas for blas routines
openmp	Use OpenMP for parallel code
qnnpack	Use QNNPACK
rocm	Enable ROCm gpu computing support
xnnpack	Use XNNPACK

cantera

hdf5	Add HDF5 container files support
python	Install Python bindings and conversion tools from Chemkin to Cantera format

cddlib

tools	Add a few executables and tests for cddlib

ceres-solver

cxsparse	Enable simple support for sparse matrix algebra from sci-libs/cxsparse with no LAPACK dependencies
gflags	Use dev-cpp/gflags for flag parsing
schur	Enable fixed-size schur specializations (disable if binary size is an issue)
sparse	Enable support for sparse matrix algebra with various packages from SuiteSparse

cfitsio

tools	Build optional utilities (cookbook fitscopy imcopy smem speed testprog fpack funpack)

cgnslib

base-scope	Enable base scoped families or connectivities
legacy	Enable or disable building legacy code (3.0 compatible)
scoping	Enable scoping of enumeration values
tools	A number of utility programs: cgnscheck, cgnscompress, cgnsdiff, cgnslist, cgnsnames, cgnsupdate, cgnsconvert, adf2hdf, hdf2adf.

cholmod

cholesky	Enable sparse Cholesky factorisation
matrixops	Support basic sparse and dense matrix operations (add, multiply, scale, et cetera)
modify	Enable Cholesky-modification routines like update, downdate, row-add, and row-delete
partition	Enable graph partitioning and graph-partition-based orderings through sci-libs/metis (using a bundled fork in 4.0.0+) or sci-libs/parmetis
supernodal	supernodal cholesky factorisation

clblas

client	Build a command line clBLAS client program.
ktest	A command line tool for testing single clBLAS kernel.
performance	Copy performance scripts that can measure and graph performance.

clblast

client	Enable compilation of the clients to test and compare performance with reference libraries
cuda	Build with support for cuda instead of opencl (beta!)

coinor-clp

glpk	Enable GNU Linear Programming Kit sci-mathematics/glpk support
metis	Enable partitioning with sci-libs/metis
mumps	Enable sci-libs/mumps support
sparse	Enable support for sparse matrix with sci-libs/cholmod

coinor-cppad

adolc	Add support for ADOL-C (sci-libs/adolc)
eigen	Add support for Eigen (dev-cpp/eigen)
ipopt	Add support for IPOPT (sci-libs/ipopt)

coinor-symphony

glpk	Enable GNU Linear Programming Kit sci-mathematics/glpk support

coinor-utils

glpk	Enable GNU Linear Programming Kit sci-mathematics/glpk support

dealii

adolc	Adds support for ADOL-C (sci-libs/adolc)
arborx	Adds support for ARBORX (sci-libs/arborx)
arpack	Adds support for ARPACK (sci-libs/arpack)
assimp	Add support for assimp (media-libs/assimp)
cgal	Adds support for CGAL (sci-mathematics/cgal)
ginkgo	Add support for ginkgo (sci-libs/ginkgo)
gmsh	Add support for gmsh (sci-libs/gmsh)
metis	Add support for metis (sci-libs/metis)
muparser	Add support for muparser (dev-cpp/muParser)
opencascade	Add support for opencascade (sci-libs/opencascade)
p4est	Add support for p4est (sci-libs/p4est)
petsc	Add support for petsc (sci-mathematics/petsc)
scalapack	Add support for ScaLAPACK (sci-libs/scalapack)
slepc	Add support for slepc (sci-mathematics/slepc)
sparse	Add support for suitesparse (sci-libs/suitesparse)
sundials	Add support for sundials (sci-libs/sundials)
symengine	Add support for symengine (sci-libs/symengine)
trilinos	Add support for trilinos (sci-libs/trilinos)

dlib

cblas	Build with CBLAS virtual/cblas
cuda	Enable support for CUDA for Deep Neural Networks (cuDNN) on GPU (experimental)
mkl	Enable support for Intel FFT sci-libs/mkl
python	Enable support for Python API bindings

dmlc-core

s3	Support for the Amazon Simple Storage Service

eccodes

defs	Install full set of definition files.
extra-test	Install full set of test data (large).
memfs	Enable memory based access to definition/sample files (conflicts with tests).

fcl

octomap	OctoMap library support
profiling	Enable profiling

fftw

zbus	Adds support for ZBus cycle-counter of mips

flann

octave	Add bindings for sci-mathematics/octave

fplll

qd	Use sci-libs/qd for quad-double datatype

gdal

armadillo	Use sci-libs/armadillo for faster TPS transform computation
fits	Enable support for NASA's sci-libs/cfitsio library
geos	Add support for geometry engine (sci-libs/geos)
gml	Enable support for dev-libs/xerces-c C++ API
ogdi	Enable support for the open geographic datastore interface (sci-libs/ogdi)
parquet	Enables read/write parquet data format (dev-libs/apache-arrow)
spatialite	Enable Spatial DBMS over sqlite dev-db/spatialite
xls	Add the dev-libs/freexl library for xls import support

ginkgo

cuda	Add support for cuda assimp (dev-util/nvidia-cuda-toolkit)
hwloc	Add support for hwloc (sys-apps/hwloc)

gloo

libuv	Enable libuv support
redis	Enable Redis backend for storage via dev-libs/hiredis

gmsh

alglib	Enable alglib support for mesh optimizers
cgns	Enables cgns output support
eigen	Build matrix manipulation with dev-cpp/eigen
gmm	A simple alternative to petsc based on sci-mathematics/gmm
med	Enables med support
metis	Enables metis support
mumps	Enables mumps solver support
netgen	Enable 3D Frontal triangulation using netgen lib
opencascade	Enable OpenCASCADE support
petsc	Enable sci-mathematics/petsc support
shared	Install shared library and headers
slepc	Enable sci-mathematics/slepc support
voro	Enable support to sci-libs/voro++ meshing

gsl

cblas-external	Link gsl with external cblas provided by (virtual/cblas) instead of shipped internal version
deprecated	Enable deprecated functions

hdf5

hl	Enable high level API (https://support.hdfgroup.org/HDF5/doc/HL/index.html)
unsupported	Enable unsupported combinations of configuration options

hipCUB

benchmark	Build and install benchmark binaries.

hipSOLVER

sparse	Build hipSOLVER with sparse functionality (sci-libs/cholmod)

hypre

int64	Build the 64 bits integer library

indilib

rtlsdr	Enable support for devices supported by net-wireless/rtl-sdr
websocket	Enable support for WebSocket protocol

ipopt

asl	AMPL Solver Library support and build the 'ipopt' binary
mumps	Enable sci-libs/mumps support

kissfft

alloca	Use alloca(3) instead of malloc(3) for memory management
double	Build library for primary data type of double
int16	Build library for primary data type of int16_t
int32	Build library for primary data type of int32_t
tools	Build command line tools

lapack

deprecated	Also build deprecated functions
eselect-ldso	Enable runtime library switching by eselect and ld.so.
lapacke	Build LAPACKE

lemon

coin	Enable the sci-libs/coinor-clp and sci-libs/coinor-cbc graph algorithms
glpk	Enable GNU Linear Programming Kit sci-mathematics/glpk support

libccd

double-precision	More precise calculations at the expense of speed

libgeodecomp

hpx	Enables HPX backend
opencv	Enables OpenCV related code
silo	Enables SILO related code

liborigin

tools	Install opj2dat command line util

libqalculate

hardened	Disable unsafe functions like 'command' and variables like 'uptime'.

libsc

romio	Build with support for the ROMIO MPI-IO component

libsigrok

ftdi	Enable drivers that need dev-embedded/libftdi
hidapi	Enable drivers that need dev-libs/hidapi
nettle	Enable drivers that need dev-libs/nettle
parport	Enable drivers that are parallel (IEEE1284) based
serial	Enable drivers that are serial (RS232) based

libsvm

tools	Install python based tool scripts for data selection and visualization with sci-visualization/gnuplot

linux-gpib

firmware	Install firmware

lis

quad	Enable quadruple precision operations
saamg	Build the Smoothed Aggregation Algebraic MultiGrid preconditioner

mathgl

hdf	Add support for the Hierarchical Data Format v.4 sci-libs/hdf
octave	Add bindings for sci-mathematics/octave

matio

sparse	Extend formats for sparse matrix (not matlab)

metis

double-precision	Use double- rather than single-precision floating-point representation
int64	Use 64- rather than 32-bit integer representation (needed for > 2^31 vertices)

mumps

metis	Enable matrix ordering with METIS (sci-libs/metis, sci-libs/parmetis)
scotch	Enable matrix ordering with sci-libs/scotch

netcdf

blosc	Allow using blosc compression via dev-libs/c-blosc
dap	Support for remote data access with the built-in OPeNDAP client
hdf	Build with HDF4 read capability(sci-libs/hdf, sci-libs/hdf5 and sys-libs/zlib required).

nlopt

octave	Add plugin for sci-mathematics/octave

octomap

dynamicEDT3D	Build and install dynamicEDT3D library: A library for incrementally updatable Euclidean distance transforms in 3D.

onnx

disableStaticReg	Disable Static Registration

openblas

dynamic	Build dynamic architecture detection at run time (for multi targets)
eselect-ldso	Enable BLAS/LAPACK runtime switching
index-64bit	Compile a separate INTERFACE64 OpenBLAS
pthread	Build with pthread threading model
relapack	Build the ReLAPACK extension to OpenBLAS

opencascade

eigen	Enable support for eigenvalues through the header-only dev-cpp/eigen package.
freeimage	Enable support for image i/o via media-libs/freeimage
freetype	Enable media-libs/freetype support
inspector	Build Inspector tool
jemalloc	Enable jemalloc allocator support via dev-libs/jemalloc
json	Enable JSON support through dev-libs/rapidjson
optimize	Don't clear allocated memory. Use optimized memory manager unlesstbb USE flag is set.
tbb	Enable multithreading with the Intel Threads Building Block dev-cpp/tbb
testprograms	Indicates whether non-regression OCCT test scripts should be installed
vtk	Enable Visualization Toolkit support via sci-libs/vtk

orocos_kdl

models	Build models for some well known robots.

p4est

romio	Build with support for the ROMIO MPI-IO component
vtk-binary	Enable binary vtk output. If disabled vtk files will be written in ASCII text format.

pastix

fortran	Install the Fortran interface
int64	Use 64- rather than 32-bit integer representation
metis	Enable matrix ordering with sci-libs/metis
scotch	Enable matrix ordering with sci-libs/scotch
starpu	Enable support for ther dev-libs/starpu runtime

pcl

openni	Adds support for Kinect-like 3D sensors devices with dev-libs/OpenNI.
openni2	Adds support for Kinect-like 3D sensors devices with dev-libs/OpenNI2 (should be preferred over openni).
pcap	Adds pcap file capabilities in some drivers.
qhull	Adds convex-hull operation support via media-libs/qhull.
tutorials	Builds and installs tutorials.
vtk	Adds support for VTK-Visualizations.

plplot

dynamic	Build with dynamic drivers
octave	Add bindings for sci-mathematics/octave
qhull	Add bindings for media-libs/qhull
shapefile	Enable support for ESRI shapefiles

rocBLAS

benchmark	Build and install rocblas-bench.
test	Perform rocblas-test to compare the result between rocBLAS and system BLAS.

rocFFT

benchmark	Build and install rocfft benchmark tools.
perfscripts	Install rocfft-perf performance visualization suite.

rocPRIM

benchmark	Build and install benchmark programs.

rocRAND

benchmark	Build and install benchmark programs.

rocSOLVER

benchmark	Build and install rocsolver-bench.
test	Perform rocsolver-test to compare the result between rocSOLVER and system LAPACK.

rocSPARSE

benchmark	Build and install rocblas-bench.

rocThrust

benchmark	Build and install benchmark binary.

rtabmap

openni2	Adds support for Kinect-like 3D sensors devices with dev-libs/OpenNI2.

scotch

int64	Build the 64 bits integer library (needed for > 2^31 vertices)
tools	Provides the graph, mesh, architecture, mapping/ordering, output handling programs (see Scotch User's Guide).

silo

browser	Enable browser support
silex	Build silex data browser

spqr

partition	Use the partition module of sci-libs/cholmod for partitioning
tbb	Enable multithreading with the Intel Threads Building Block dev-cpp/tbb

spr

root	Add sci-physics/root graphics and i/o support

suitesparse

partition	Enable graph partitioning and graph-partition-based orderings through sci-libs/metis or sci-libs/parmetis
tbb	Enable multithreading with the Intel Threads Building Block dev-cpp/tbb

sundials

hypre	Build with sci-libs/hypre conditioners
int64	Use index size of 64 rather than 32 bits
sparse	Enable support for sci-libs/klu sparse solver
superlumt	Build with sci-libs/superlu_mt

superlu_mt

int64	Build the 64 bits integer library

symengine

arb	Add support for arb (sci-mathematics/arb)
benchmarks	Build benchmarks
boost	Add support for boost integers(dev-libs/boost)
ecm	Add support for ECM integer factorization library (sci-mathematics/gmp-ecm)
flint	Add support for (sci-mathematics/flint)
llvm	Build with LLVM
mpc	Add support for multiprecision complex arithmetic(dev-libs/mpc)
mpfr	Add support for multiprecision floating point rouding(dev-libs/mpfr)

trilinos

adolc	Add support for adolc (sci-libs/adolc)
all-packages	Enable all supported Trilinos packages (per default only a subset is built)
arprec	Add support for arprec (sci-libs/arprec)
clp	Add support for clp (sci-libs/coinor-clp)
eigen	Add support for eigen (dev-cpp/eigen)
glpk	Add support for glpk (sci-mathematics/glpk)
gtest	Add support for gtest (dev-cpp/gtest)
hdf5	Add support for hdf5 (sci-libs/hdf5)
hwloc	Add support for hwloc (sys-apps/hwloc)
hypre	Add support for hypre (sci-libs/hypre)
matio	Add support for matio (sci-libs/matio)
metis	Add support for metis (sci-libs/metis or sci-libs/parmetis)
mkl	Add support for mkl (sci-libs/mkl)
mumps	Add support for mumps (sci-libs/mumps)
netcdf	Add support for netcdf (sci-libs/netcdf)
petsc	Add support for petsc (sci-mathematics/petsc)
qd	Add support for qd (sci-libs/qd)
scalapack	Add support for scalapack (sci-libs/scalapack)
scotch	Add support for scotch (sci-libs/scotch)
sparse	Add support for sparse matrix solvers (sci-libs/umfpack)
superlu	Add support for superlu (sci-libs/superlu)
taucs	Add support for taucs (sci-libs/taucs)
tbb	Add support for threading building blocks library (dev-cpp/tbb)
tvmet	Add support for tvmet (dev-libs/tvmet)
yaml	Add support for yaml (dev-cpp/yaml-cpp)

umfpack

cholmod	Use sci-libs/cholmod for matrix ordering

vtk

all-modules	Build all modules
boost	Add support for boost
freetype	Build support for font rendering
gdal	Support for gdal formated data
imaging	Building Imaging modules
las	Build support for LiDAR files
logging	Build the logging module
opencascade	Enable OpenCASCADE support
openvdb	Build support to handle VDB data files
pdal	Build support to handle point cloud data files
qt6	Use Qt6 packages instead of Qt5
rendering	Building Redering modules
sdl	Enable SDL2 support for rendering modules
tbb	Use dev-cpp/tbb to handle smp support
views	Building Views modules
vtkm	Build the vtkm accelerations modules
web	Install web component

sci-mathematics

bertini

optimization	Accept upstream's choices for -O option.

boolector

cryptominisat	Enable support for sci-mathematics/cryptominisat
minisat	Enable support for sci-mathematics/minisat
picosat	Enable support for sci-mathematics/picosat

cadabra

jupyter	Build the Cadabra Jupyter kernel

cvc4

cln	Use sci-libs/cln
proofs	Support for proof generation
statistics	Include statistics

eclib

boost	Add parallel capabilities using dev-libs/boost.
flint	Enable the use of sci-mathematics/flint for certain operations.
minimal	Build only the "mwrank" program.

eprover

ho	enable support for higher-order logic

flint

ntl	Build NTL interface

form

devref	Build and install developers reference
doxygen	Build and install API documentation

fricas

clisp	Add support for GNU CLISP (dev-lisp/clisp)
clozurecl	Add support for Clozure Common Lisp (dev-lisp/clozurecl)
cmucl	Add support for CMU Common Lisp (dev-lisp/cmucl)
ecl	Add support for Embeddable Common Lisp (dev-lisp/ecl)
gcl	Add support for GNU Common Lisp (dev-lisp/gcl)
sbcl	Add support for Steel Bank Common Lisp (dev-lisp/sbcl)

gap

memcheck	Enable memory checking
minimal	Install only the GAP packages that are strictly required for GAP to run. GAP will complain about the others unless you either start it with the "-A" flag or set "AutoloadPackages" in your gap.ini.

geomview

motionaveraging	Enable experimental motion averaging technique

giac

ecm	Enable the use of sci-mathematics/gmp-ecm
gc	Enable garbage collection support via dev-libs/boehm-gc
glpk	Enable the use of sci-mathematics/glpk

gmp-ecm

custom-tune	Improve performance of some operations by selecting machine-specific defaults

gretl

R	Enable support for dev-lang/R
extras	Build and install add-ons bundled with gretl

lcalc

double	Use double precision (the upstream default)
double-double	Use sci-libs/qdfor double-double precision
pari	Use sci-mathematics/pari for elliptic curve L-functions
quad-double	Use sci-libs/qdfor quad-double precision

mathematica

R	Enable dev-lang/R backend support
bundle	Install from Wolfram's bundle file or from Mathematica only
ffmpeg	Enable media-video/ffmpeg backend support

maxima

clisp	Compile maxima with GNU CLISP (dev-lisp/clisp)
clozurecl	Compile maxima with 32-bit Clozure Common Lisp (dev-lisp/clozurecl)
clozurecl64	Compile maxima with 64-bit Clozure Common Lisp (dev-lisp/clozurecl)
cmucl	Compile maxima with CMU Common Lisp (dev-lisp/cmucl)
ecl	Compile maxima with Embeddable Common Lisp (dev-lisp/ecl)
gcl	Compile maxima with GNU Common Lisp (dev-lisp/gcl)
sbcl	Compile maxima with Steel Bank Common Lisp (dev-lisp/sbcl)
vtk	Support plotting with sci-libs/vtk

msieve

ecm	Enable support for the GMP-ECM library

normaliz

extras	Install Macaulay2 and sci-mathematics/singularpackages as shipped by upstream
nauty	Use sci-mathematics/nauty to compute automorphism groups.

octave

fltk	Use x11-libs/fltk as the backend for the OpenGL renderer in the absence of the Qt GUI
glpk	Add support for sci-mathematics/glpk for linear programming
gnuplot	Use sci-visualization/gnuplot to render plots if OpenGL is unavailable
imagemagick	Use media-gfx/graphicsmagick to read and write images
json	Allow using jsonencode and jsondecode commands via dev-libs/rapidjson
klu	Add support for KLU (sci-libs/klu)
qhull	Add support for media-libs/qhull, to allow `delaunay', `convhull', and related functions
qrupdate	Add support for sci-libs/qrupdatefor QR and Cholesky update functions
sparse	Add enhanced support for sparse matrix algebra with SuiteSparse
spqr	Add support for SPQR (sci-libs/spqr)
sundials	Enable the ode15i and ode15s ODE solvers using sci-libs/sundials

pari

data	Add additional data (elldata, galdata, seadata, nftables)

petsc

afterimage	Use Afterstep image library (media-libs/libafterimage)
boost	Use boost (dev-libs/boost)
complex-scalars	Make scalars complex
hypre	Use HYPRE (sci-mathematics/hypre) and for preconditioning
int64	Use 64 bit indexes
metis	Add support for metis (sci-libs/parmetis)
mumps	Add support for mumps (sci-libs/mumps)
scotch	Add support for scotch (sci-libs/scotch)
sparse	Use suitesparse (sci-libs/suitesparse) including cholmod (sci-libs/cholmod) for sparse factorization
superlu	Use superlu (sci-libs/superlu) for preconditioning

polymake

bliss	Enable sci-libs/bliss interface for graph and face lattice isomorphism computations.
cdd	Enable sci-libs/cddlib interface for convex hull computations (Should be kept enabled).
flint	Build with "strongly recommended" support for sci-mathematics/flint.
libpolymake	Build the polymake library to build applications using the C++ interface.
lrs	Enable sci-libs/lrslib interface for convex hull computations.
nauty	Build the extension for graph automorphism computations using sci-mathematics/nauty.
normaliz	Build the bundled extension for lattice computations using sci-mathematics/normaliz.
ppl	Enable dev-libs/ppl interface for convex hull computations.
singular	Enable the interface to sci-mathematics/singular for ideal related computations.

primecount

executable	Build the primecount CLI executable

primesieve

executable	Build the primesieve CLI executable

singular

polymake	Enable the interface to TOPCOM

slepc

arpack	Adds support for ARPACK (sci-libs/arpack)
complex-scalars	Make scalars complex

stp

cryptominisat	Enable sci-mathematics/cryptominisat support
python	Enable building the Python interface

unuran

prng	Use sci-mathematics/prng library
rngstreams	Use sci-mathematics/rngstreams library

vampire

z3	Enable support for sci-mathematics/z3

why3

coq	Add sci-mathematics/coq support
gtk	Build the IDE x11-libs/gtk+
re	Use Re (dev-ml/re) instead of Str for regular expressions
sexp	Add support for outputting S-expressions with dev-ml/ppx_sexp_conv
stackify	Enable structure reconstruction algorithm for MLCFG
zarith	Use Zarith (dev-ml/zarith) instead of Nums (dev-ml/num) for computations
zip	Enable compression of session files

why3-for-spark

coq	Add sci-mathematics/coq support
html	Build HTML documentation
hypothesis-selection	Enable hypothesis selection
sexp	Add support for outputting S-expressions with dev-ml/ppx_sexp_conv
zarith	Use Zarith (dev-ml/zarith) instead of Nums (dev-ml/num) for computations
zip	Enable compression of session files

wxmaxima

webkit	Use net-libs/webkit-gtk to show help (for maxima and wxmaxima) inside wxmaxima

yacas

jupyter	Add support for jupyter notebook

yices2

mcsat	Enable support for MCSAT

z3

isabelle	Add integration support for the Isabelle/HOL theorem prover.

sci-misc

h5utils

hdf	Build hdf to hdf5 (and vice-versa) converter
octave	Build Octave plugins

nco

dap	Support for remote data access with the NETCDF DAP client
ncap2	Build next generation netcdf arithmetic processor (needs dev-java/antlr)
udunits	Add sci-libs/udunits files support

sci-physics

bullet

double-precision	Build libraries in double precision
extras	Build the extras
tbb	Enable multithreading with the Intel Threads Building Block dev-cpp/tbb

espresso

examples	Installs the examples

fastjet

cgal	Use sci-mathematics/cgal instead of bundled algorithms
plugins	Build all standard and C++ plugins

geant

data	Add a lot of standard physics data files for geant4
freetype	Add support for media-libs/freetype
gdml	Enable geometry markup language for xml
geant3	Add compatibility for geant321 to geant4
inventor	Add support for Open Inventor SGI toolkit via Coin3D
raytracerx	Enable raytracing for physics events
tbb	Enable support for dev-cpp/tbb
trajectories	Enable display of particle trajectories
vtk	Use sci-libs/vtk for visualization (experimental)

geant4_vmc

g4root	Build G4Root (interface for GEANT4 simulation with a ROOT geometry)
geant3	Build with Geant4 G3toG4 library
vgm	Enable the Virtual Geometry Model (sci-physics/vgm)

hepmc

cm	Build with cm instead of default mm for length units
gev	Build with GeV instead of default MeV for momentum units
root	Build with ROOTIO enabled

lammps

extra	Additional compute, dump, fix, molecular, pair styles
hip	Enable hip gpu computing support
lammps-memalign	Enables the use of the posix_memalign() call instead of malloc() when large chunks or memory are allocated by LAMMPS. Aliengnment is on 16 byte boundaries.

pythia

fastjet	Build jets using the sci-physics/fastjet package
hepmc	Adds support for High Energy Physics Monte Carlo Generators sci-physics/hepmc
hepmc2	Adds support for High Energy Physics Monte Carlo Generators 2 sci-physics/hepmc
hepmc3	Adds support for High Energy Physics Monte Carlo Generators 3 sci-physics/hepmc
highfive	Support hdf and highfive
lhapdf	Support the use of external PDF sets via sci-physics/lhapdf
mpich	Support mpich
rivet	Support sci-physics/rivet
root	Use sci-physics/root trees and histograms (in examples only)

rivet

hepmc2	Build with HepMC2
hepmc3	Build with HepMC3
highfive	Build with hdf5 and highfive
zlib	Build with zlib

root

R	Enable support for dev-lang/R
asimage	Enable support for media-libs/libafterimage
cudnn	Enable support for nVidia cuDNN library
davix	Enable support for DAVIX Data Management Client (https://cern.ch/davix)
fits	Enable support for images and data from FITS files with sci-libs/cfitsio
fortran	Compile included Fortran programs
gdml	Enable GDML writer and reader
http	Enable http server support including but not limited to fastcgi support
jupyter	Install dependencies to enable ROOT's C++ kernel in Jupyter notebooks
libcxx	Build ROOT against sys-libs/libcxx
minuit	Build ROOT's internal versions of minuit (fortran) and minuit2 (C++)
pythia6	Build the interface for sci-physics/pythia version 6.x
pythia8	Build the interface for sci-physics/pythia version 8.x
roofit	Build RooFit function fitting package
root7	Build experimental features to be released with ROOT 7
shadow	Enable shadow authentication in rootd and proofd
tbb	Enable implicit multi-threading (IMT) with dev-cpp/tbb
tmva	Built TMVA (ROOT's multi-variate analysis toolkit for machine learning)
unuran	Enable support for sci-mathematics/unuran
uring	Enable support for sys-libs/liburing in RNTuple
vc	Enable support for dev-libs/vc with VecCore
xrootd	Build the interface for net-libs/xrootd

thepeg

fastjet	Adds support for sci-physics/fastjet
hepmc	Adds support for High Energy Physics Monte Carlo Generatorssci-physics/hepmc
hepmc3	Adds support for High Energy Physics Monte Carlo Generators 3sci-physics/hepmc
lhapdf	Adds support for sci-physics/lhapdf
rivet	Adds support for sci-physics/rivet

vgm

geant4	Enable interaction with Geant4(sci-physics/geant:4)
root	Enable interaction with ROOT (sci-physics/root)

yoda

root	Adds support for sci-physics/root

sci-visualization

fityk

nlopt	Enable optimization with sci-libs/nlopt

gnuplot

amos	Enable Amos routines for complex Airy and Bessel functions (dev-libs/openspecfun)
bitmap	Enable dot-matrix printers and pbm terminal
gd	Add support for media-libs/gd. Needed for GIF, JPEG, and PNG image output.
gpic	Include support for gpic terminal
libcerf	Enable special functions from sci-libs/libcerf
metafont	Include support for metafont terminal
metapost	Include support for metapost terminal
regis	Include support for ReGIS terminal
tgif	Include support for tgif terminal

gr

agg	Enable the libagg anti-grain rendering engine

gwyddion

fits	Enable FITS image import via sci-libs/cfitsio
jansson	Enable JSON data manipulation via dev-libs/jansson
sourceview	Enable support for x11-libs/gtksourceview
unique	Enable remote control backend via dev-libs/libunique

labplot

eigen	Enable support for fast baseline removal via dev-cpp/eigen
fits	Enable support for NASA's sci-libs/cfitsio library
libcerf	Enable special functions from sci-libs/libcerf
markdown	Enable Markdown support via app-text/discount
matio	Enable support for matio (sci-libs/matio)
ods	Enable support for importing/exporting OpenDocument spreadsheets (.ods) via dev-libs/liborcus
origin	Enable support for reading OriginLab OPJ project files through sci-libs/liborigin
root	Enable support for CERN's ROOT file type
serial	Enable support for RS232 serial ports using dev-qt/qtserialport
share	Enable support for a share menu using kde-frameworks/purpose
xlsx	Enable support for importing/exporting Microsoft Excel files (.xlsx) via dev-libs/qxlsx

paraview

boost	Enable the usage of dev-libs/boost
cg	Add support for nvidia's cg shaders
nvcontrol	Add NVCONTROL support for OpenGL options
offscreen	Offscreen rendering through OSMesa
plugins	Build and install additional plugins
webengine	Add support for dev-qt/qtwebengine

scidavis

origin	Add support for reading OriginLab OPJ project files through sci-libs/liborigin.
python	Build support for python scripting.

sec-policy

selinux-base

ubac	Enable User Based Access Control (UBAC) in the SELinux policy
unconfined	Enable support for the unconfined SELinux module
unknown-perms	Default allow unknown classes in kernels newer than the policy (SELinux policy capability).

selinux-base-policy

unconfined	Enable support for the unconfined SELinux policy module

sys-apps

accountsservice

elogind	Use sys-auth/elogind for session tracking
systemd	Use sys-apps/systemd for session tracking

bfs

io-uring	Use sys-libs/liburing for faster async I/O

busybox

make-symlinks	Create all the appropriate symlinks in /bin and /sbin.
math	Enable math support in gawk (requires libm)
mdev	Create the appropriate symlink in /sbin and install mdev.conf and support files
sep-usr	Support a separate /usr without needing an initramfs by booting with init=/ginit
static	Make the system rescue shell (/bin/bb) static so you can recover even when glibc is broken
systemd	Support systemd

coreutils

caps	Add Linux capabilities support in output of file utilities (ls, dir, ...) via sys-libs/libcap
hostname	Build the hostname program
kill	Build the kill program
multicall	Build all tools into a single `coreutils` program akin to busybox to save space
openssl	Use openssl libcrypto hash routines for hash functions
split-usr	Enable this if /bin and /usr/bin are separate directories

cpu-x

cpu	Use the dev-libs/libcpuid library for CPU info
force-libstatgrab	Use sys-libs/libstatgrab to instead of sys-process/procps
gpu	Use the media-libs/glfw library for GPU info
pci	Use the sys-apps/pciutils library for PCI info

dbus

elogind	Use sys-auth/elogind for session tracking.
systemd	Build with sys-apps/systemd at_console support

dbus-broker

launcher	dbus-daemon compatibility launcher

dtc

yaml	support .yaml-encoded device trees

duc

X	Use X11 for the GUI instead of OpenGL. This is the recommended option
cairo	Build support for exporting to PNG and PDF with x11-libs/cairo
leveldb	Use dev-libs/leveldb as the backend
ncurses	Build support for the ncurses client
sqlite	Use dev-db/sqlite:3 as the backend
tokyocabinet	Use dev-db/tokyocabinet as the backend

elfix

ptpax	Enable PT_PAX_FLAGS support.
xtpax	Enable XATTR_PAX_FLAGS support.

etckeeper

cron	Install cron script

ethtool

netlink	Enable netlink interface via net-libs/libmnl

firejail

X	Enable X11 sandboxing
apparmor	Enable support for custom AppArmor profiles
chroot	Enable chrooting to custom directory
contrib	Install contrib scripts
dbusproxy	Enable DBus proxying to filter access in supporting profiles
file-transfer	Enable file transfers between sandboxes and the host system
globalcfg	Enable global config file
network	Enable networking features
private-home	Enable private home feature
userns	Enable attaching a new user namespace to a sandbox (--noroot option)

flashrom

atahpt	Highpoint (HPT) ATA/RAID controller support
atapromise	Support for Promise PDC2026x (FastTrak/Ultra)
atavia	Support for VIA VT6421A SATA controllers
buspirate-spi	Enable Bus Pirate SPI programmer
ch341a-spi	Enable WCH CH341A SPI programmer
dediprog	Dediprog SF100 support
developerbox-spi	Enable Devloperbox SPI recovery support
digilent-spi	Enable support for Digilent iCEblink40 development board
dirtyjtag-spi	Support for DirtyJTAG (a USB-JTAG firmware for STM32 MCUs)
drkaiser	Enable Dr. Kaiser programmer
dummy	Enable dummy tracing
ft2232-spi	Enable ftdi programmer, flashing through FTDI/SPI USB interface
gfxnvidia	Enable NVIDIA programmer
internal	Enable internal/onboard support
internal-dmi	Enable internal DMI decoding rather than use sys-apps/dmidecode
it8212	Support for ITE IT8212F ATA/RAID controllers
jlink-spi	Support for SEGGER J-Link and compatible devices
linux-mtd	Enable support for Linux mtd SPI flash devices
linux-spi	Enable support for Linux userspace spidev interface
mediatek-i2c-spi	Support for Mediatek LCD controllers
mstarddc-spi	Support for SPI flash ROMs accessible through DDC in MSTAR-equipped displays
nic3com	Enable 3Com NIC programmer
nicintel	Support for Intel NICs
nicintel-eeprom	Support for EEPROMs on Intel Gigabit network cards
nicintel-spi	Support for SPI on Intel NICs
nicnatsemi	Support for National Semiconductor NICs
nicrealtek	Support for Realtek NICs
ogp-spi	Enable support for OGP (Open Graphics Project) SPI flashing
parade-lspcon	Enable support for Parade lspcon USB-C to HDMI protocol translator
pickit2-spi	Support for SPI flash ROMs accessible via Microchip PICkit2
pony-spi	Enable support for SI-Prog like hardware by Lancos
raiden-debug-spi	Support for Chrome EC based debug tools - SuzyQable, Servo V4, C2D2 & uServo
rayer-spi	RayeR SPIPGM hardware support
realtek-mst-i2c-spi	Enable support for Realtek RTD2142 MST
satamv	Enable programmer for Marvell SATA controllers
satasii	Enable programmer for SiI SATA controllers
serprog	Enable Serial Flasher programmer
stlinkv3-spi	Enable SPI programmer using STLINK-V3
tools	Install ich_descriptor_tool, a tool for reading descriptor-mode SPI-flash images for Intel chipsets
usbblaster-spi	Enable support for Altera USB-Blaster dongles

fwupd

amdgpu	Build and install AMD dGPU (Navi3x and above) plugin
amt	Build and install Intel AMT plugin
archive	Use app-arch/libarchive for archives support
cbor	Enable CBOR support for coSWID and uSWID via dev-libs/libcbor
fastboot	Build and install fastboot plugin
flashrom	Enable flashrom plugin via sys-apps/flashrom
gusb	Enable dev-libs/libgusb support
logitech	Build and install Logitech bulk controller plugin
modemmanager	Build and install Modem Manager plugin
nvme	Build and install NVMe plugin
spi	Install Intel-SPI plugin
synaptics	Install synaptics plugin
test-full	Enable tests known not to play nicely with the sandbox
tpm	Install Trusted Platform Module plugin
uefi	Enable UEFI support

gawk

mpfr	Use dev-libs/mpfr for high precision arithmetic (-M / --bignum)
pma	Experimental Persistent Memory Allocator (PMA) support which allows persistence of variables, arrays, and user-defined functions across runs.

gnome-disk-utility

fat	Include FAT16/FAT32 support (sys-fs/dosfstools)

grep

egrep-fgrep	Install deprecated 'egrep' and 'fgrep' wrappers for 'grep -E' and 'grep -F' respectively. GNU grep 3.8 onwards warns about their usage by default, but the versions installed by this flag do not. No deprecation warnings are emitted when this flag is enabled.

groff

uchardet	Enable automatic encoding detection via app-i18n/uchardet

hwloc

X	use the X Window System
cairo	Enable the Cairo back-end of hwloc's lstopo command
cpuid	Enable the cpuid-based architecture specific support (x86 component)
cuda	Enable CUDA device discovery using libcudart
gl	Enable GL display device discovery (NVCtrl)
l0	Enable oneAPI Level Zero device discovery
numa	Add support for numa memory allocation
nvml	Enable the NVML device discovery
pci	Enable PCI device discovery using libpci
plugins	Build hwloc components as plugins so that the hwloc core library does not directly depend on their dependencies (for instance the libpci library)
rocm	Enable AMD RSMI device discovery
xml	use libxml2 for XML support, instead of a custom minimalistic support

ibm-powerpc-utils

rtas	Add support for the Run Time Abstraction Services (RTAS)

iotools

make-symlinks	Generate sub-command symlinks to iotools -- note that a lot are simple like "xor"

ipmicfg

uefi	Install compatible UEFI file for boot.

ipmitool

openbmc	Enable OpenBMC D-Bus interface
openipmi	Use the system OpenIPMI implementation.

iproute2

berkdb	build programs that use berkdb (just arpd)
bpf	Use dev-libs/libbpf
elf	support loading eBPF programs from ELFs (e.g. LLVM's eBPF backend)
iptables	include support for iptables filtering
minimal	only install ip and tc programs, without eBPF support
nfs	Support RPC lookups via net-libs/libtirpc in ss

irqbalance

numa	Support balancing IRQs across NUMA nodes
thermal	Enable support of thermal events via sys-power/thermald
tui	Enable build of irqbalance terminal user interface

kexec-tools

booke	Include support for Book-E memory management
lzma	Enables support for LZMA compressed kernel images
xen	Enable extended xen support

kmod

lzma	Enable support for XZ compressed modules
pkcs7	Enable PKCS#7 signature parsing for modinfo.
tools	Install module loading/unloading tools.
zlib	Enable support for gzipped modules

kmscon

drm	Enable Linux DRM for backend
fbdev	Enable Linux FBDev for backend
pango	Enable pango font rendering
pixman	Enable pixman font rendering
systemd	Enable multiseat support via systemd

linux-misc-apps

usbip	Include USB/IP binaries to replace net-misc/usbip

lm-sensors

contrib	Installs user contributed configuration files so you don't need to find settings on your own for your system if somebody else has already created such a configuration for sensors/mainboards you are using.
sensord	Enable sensord - a daemon that can be used to periodically log sensor readings from hardware health-monitoring chips

man-db

manpager	Enable manpager wrapper for colorizing output

memtest86+

bios32	Compile a BIOS-bootable 32bit memtest image
bios64	Compile a BIOS-bootable 64bit memtest image
boot	Install to /boot in addition to /usr/share/memtest86+/
iso32	Compile a 32bit ISO image
iso64	Compile a 64bit ISO image
uefi32	Compile a EFI32-bootable 32bit memtest image
uefi64	Compile a UEFI-bootable 64bit memtest image

moreutils

perl	Install scripts written in Perl

net-tools

arp	build the arp and rarp tools (for manipulating the ARP cache)
hostname	build the hostname and dnsdomainname tools
plipconfig	build the plipconfig tool (for working with old PLIP hardware)
slattach	build the slattach tool (for working with old serial ports)

nvme-cli

json	Support JSON output via dev-libs/json-c
pdc	Set default Persistent Discovery Controllers behavior

openrazer

client	Build the OpenRazer daemon client
daemon	Build the OpenRazer daemon service

openrc

bash	enable the use of bash in service scripts (experimental)
netifrc	enable Gentoo's network stack (net.* scripts)
newnet	enable the new network stack (experimental)
s6	install s6-linux-init
sysv-utils	Install sysvinit compatibility scripts for halt, init, poweroff, reboot and shutdown
sysvinit	control the dependency on sysvinit (experimental)

openrc-navi

bash	enable the use of bash in service scripts (experimental)
netifrc	enable Gentoo's network stack (net.* scripts)
newnet	enable the new network stack (experimental)
s6	install s6-linux-init
sysv-utils	Install sysvinit compatibility scripts for halt, init, poweroff, reboot and shutdown
sysvinit	control the dependency on sysvinit (experimental)

pciutils

dns	Enable support for querying the central database of PCI IDs using DNS
kmod	Enable sys-apps/kmod support for the -k switch in lspci command
zlib	Support compressed pci.ids database

pcmciautils

staticsocket	Add support for static sockets

pcsc-lite

embedded	limit RAM and CPU ressources by disabling features
libusb	Use dev-libs/libusb detection to hotplug new smartcard readers. This flag should only be enabled if you're running a non-Linux kernel or you don't want to use udev.
policykit	Uses sys-auth/polkit to restrict access to smartcard readers or smartcards to given users.
udev	Use virtual/libudev rules to handle devices' permissions and hotplug support. Unless you know what you're doing do not disable this flag on Linux kernels. This is provided as an option for completeness.

pcsc-tools

network-cron	Install a monthly cronjob to update the update-smartcard_list script

plocate

io-uring	Enable efficient I/O via sys-libs/liburing.

policycoreutils

audit	Enable support for sys-process/audit and use the audit_* functions (like audit_getuid instead of getuid())

portage

apidoc	Build html API documentation with sphinx-apidoc.
gentoo-dev	Enable features required for Gentoo ebuild development.
ipc	Use inter-process communication between portage and running ebuilds.
native-extensions	Compiles native "C" extensions (speedups, instead of using python backup code). Currently includes libc-locales. This should only be temporarily disabled for some bootstrapping operations. Cross-compilation is not supported.
rsync-verify	Enable full-tree cryptographic verification of Gentoo repository rsync checkouts using app-portage/gemato.
xattr	Preserve extended attributes (filesystem-stored metadata) when installing files. Usually only required for hardened systems.

ppc64-diag

rtas	Add support for the Run Time Abstraction Services (RTAS)

proot

care	Build dynamic CARE binary (more info - https://proot-me.github.io)

razercfg

gui	Installs GUI configuration utility and status bar applet. Requires dev-python/PyQt5

rng-tools

jitterentropy	Enable Jitter RNG entropy support
nistbeacon	Enable NIST beacon entropy support
pkcs11	Enable PKCS11 entropy support
qrypt	Enable qrypt beacon entropy support
rtlsdr	Enable atmospheric-static entropy support with net-wireless/rtl-sdr

s390-tools

cryptsetup	build the zkey-cryptsetup utility (requires USE=openssl)
fuse	build cmsfs-fuse to read files stored on a z/VM CMS disk
ncurses	build hyptop monitoring program
openssl	build the zkey utility
pfm	build the cpacfstats tool
zlib	build the zgetdump and dump2tar utilities

s6

execline	enable support for dev-lang/execline

s6-linux-init

sysv-utils	Install sysvinit compatibility symlinks for telinit, halt, poweroff, reboot, and shutdown

sandbox

nnp	Enable NO_NEW_PRIVS which blocks set*id programs from gaining privileges (e.g. sudo)

shadow

su	build the su program

smartmontools

caps	Build against sys-libs/libcap-ng to allow smartd to drop its privileges.
daemon	Install the monitoring daemon (smartd) and associated scripts.
update-drivedb	Install a script to update the drivedb file.

smc-sum

module	Install Supermicro's kernel module.

superdiag

iso	Install an iso image, which can be used with sys-apps/smc-sum.
usb	Install all files, which are needed for an installation on an usb thumb drive.

systemd

audit	Enable support for sys-process/audit
boot	Enable EFI boot manager and stub loader
bpf	Enable BPF support for sandboxing and firewalling.
cgroup-hybrid	Default to hybrid (legacy) cgroup hierarchy instead of unified (modern).
cryptsetup	Enable cryptsetup tools (includes unit generator for crypttab)
curl	Enable support for uploading journals
dns-over-tls	Enable DNS-over-TLS support
elfutils	Enable coredump stacktraces in the journal
fido2	Enable FIDO2 support
gcrypt	Enable use of dev-libs/libgcrypt for various features
homed	Enable portable home directories
http	Enable embedded HTTP server in journald
importd	Enable import daemon
iptables	Use libiptc from net-firewall/iptables for NAT support in systemd-networkd; this is used only if the running kernel does not support nftables
kernel-install	Enable kernel-install
kmod	Enable kernel module loading via sys-apps/kmod
lz4	Enable lz4 compression for the journal
openssl	Enable use of dev-libs/openssl for various features
pkcs11	Enable PKCS#11 support for cryptsetup and homed
pwquality	Enable password quality checking in homed
qrcode	Enable qrcode output support in journal
resolvconf	Install resolvconf symlink for systemd-resolve
sysv-utils	Install sysvinit compatibility symlinks and manpages for init, telinit, halt, poweroff, reboot, runlevel, and shutdown
tpm	Enable TPM support
ukify	Enable systemd-ukify
vanilla	Disable Gentoo-specific behavior and compatibility quirks
xkb	Depend on x11-libs/libxkbcommon to allow logind to control the X11 keymap

systemd-utils

boot	Enable systemd-boot (UEFI boot manager)
kernel-install	Enable kernel-install
kmod	Enable kernel module loading via sys-apps/kmod
sysusers	Enable systemd-sysusers
tmpfiles	Enable systemd-tmpfiles
udev	Enable systemd-udev (userspace device manager)
ukify	Enable systemd-ukify

tcp-wrappers

netgroups	Support matching NIS (host) netgroup names via the @netgroup syntax (if you don't know what this means, you most likely do not need it)

texinfo

standalone	Build standalone version that survives all Portage bugs

usbguard

umockdev	Enables support for dev-util/umockdev

usermode-utilities

fuse	Build tools (currently umlmount) needing fuse

util-linux

audit	Use sys-process/audit to emit audit messages about system changes
caps	build setpriv helper (run programs with diff capabilities)
cramfs	build mkfs/fsck helpers for cramfs filesystems
cryptsetup	Use sys-fs/cryptsetup to have built-in dm-verity in libmount
fdformat	build fdformat (floppy disk format)
hardlink	build hardlink program
kill	build the kill program
logger	build the logger program
pam	build runuser helper
rtas	Add support for the Run Time Abstraction Services (RTAS)
su	build the su program
suid	Install some programs with suid bit set to provide additional functionality. mount/umount: non-root users may mount/umount devices wall/write: non-root users can notify other users su: non-root users may become root
tty-helpers	install the mesg/wall/write tools for talking to local users
uuidd	build uuidd daemon

watchdog

nfs	enable support for checking nfs mounts

xdg-desktop-portal

flatpak	Enable sys-apps/flatpak integration
seccomp	Use sys-apps/bubblewrap (which requires seccomp) to sandbox some functionality like icon handling

xinetd

rpc	support RPC services

sys-auth

elogind

cgroup-hybrid	Use hybrid cgroup hierarchy instead of unified (OpenRC's default).

munge

gcrypt	Use libgcrypt instead of openssl

nss-pam-ldapd

pynslcd	Install the python implementation along with the standard implementation
utils	Install the command-line utilities

oath-toolkit

pam	Build PAM module for pluggable login authentication for OATH

pam_mktemp

prevent-removal	If supported, set EXT2_APPEND_FL on /tmp/.private to prevent temporary directories from being removed

pam_mysql

openssl	Use OpenSSL for md5 and sha1 support

pam_u2f

debug	Enable debug messages using the pam logging macros.

pambase

debug	Enable debug information logging on syslog(3) for all the modules supporting this in the system authentication and system login stacks.
elogind	Use pam_elogind module to register user sessions with elogind.
homed	Use pam_systemd_home module to manage home directories with the systemd-homed service
minimal	Disables the standard PAM modules that provide extra information to users on login; this includes pam_lastlog, pam_motd, pam_mail and other similar modules. This might not be a good idea on a multi-user system but could reduce slightly the overhead on single-user non-networked systems.
mktemp	Enable pam_mktemp module on system auth stack for session handling. This module creates a private temporary directory for the user, and sets TMP and TMPDIR accordingly.
nullok	Enable the nullok option with the pam_unix module. This allows people to login with blank passwords.
pam_krb5	Enable pam_krb5 module on system auth stack, as an alternative to pam_unix. If Kerberos authentication succeeds, only pam_unix will be ignorde, and all the other modules will proceed as usual, including Gnome Keyring and other session modules. It requires sys-libs/pam as PAM implementation.
pam_ssh	Enable pam_ssh module on system auth stack for authentication and session handling. This module will accept as password the passphrase of a private SSH key (one of ~/.ssh/id_rsa, ~/.ssh/id_dsa or ~/.ssh/identity), and will spawn an ssh-agent instance to cache the open key.
passwdqc	Enable pam_passwdqc module on system auth stack for password quality validation. This module produces warnings, rejecting or providing example passwords when changing your system password. It is used by default by OpenWall GNU/*/Linux and by FreeBSD.
pwhistory	Enable pam_pwhistory module on system auth stack to save the last passwords for each user in order to force password change history and keep the user from alternating between the same password too frequently.
pwquality	Enable pam_pwquality module on system auth stack for passwd quality validation. It is used by default by Fedora GNU/*/Linux.
securetty	Enable pam_securetty module in the login stack. Not generally relevant anymore as the login stack only refers to local logins and local terminals imply secure access in the first place.
sha512	Switch Linux-PAM's pam_unix module to use sha512 for passwords hashes rather than MD5. This option requires sys-libs/pam version 1.0.1 built against sys-libs/glibc version 2.7, if it's built against an earlier version, it will silently be ignored, and MD5 hashes will be used. All the passwords changed after this USE flag is enabled will be saved to the shadow file hashed using SHA512 function. The password previously saved will be left untouched. Please note that while SHA512-hashed passwords will still be recognised if the USE flag is removed, the shadow file will not be compatible with systems using an earlier glibc version.
sssd	Add System Security Services Daemon (sys-auth/sssd) support via pam_sss.
systemd	Use pam_systemd module to register user sessions in the systemd control group hierarchy.
yescrypt	Switch Linux-PAM's pam_unix module to use yescrypt for passwords hashes rather than MD5

polkit

daemon	Build polkitd in addition to libpolkit.
duktape	Use dev-lang/duktape instead of dev-lang/spidermonkey as JavaScript engine
systemd	Use sys-apps/systemd for session tracking

seatd

builtin	Enable embedded server in libseat
server	Enable standalone seatd server, replacement to (e)logind

ssh-ldap-pubkey

schema	Install a copy of the LPK schema, only needed on LDAP servers.

sssd

acl	Build and use the cifsidmap plugin
netlink	Add support for netlink protocol via dev-libs/libnl
nfsv4	Add support for the nfsv4 idmapd plugin provided by net-fs/nfs-utils
samba	Add Privileged Attribute Certificate Support for Kerberos
subid	Support subordinate uid and gid ranges in FreeIPA
sudo	Build helper to let app-admin/sudo use sssd provided information
systemtap	Enable SystemTap/DTrace tracing

sys-block

f3

extra	Build the additional f3probe, f3brew and f3fix utility (requires sys-block/parted and virtual/udev)

fio

aio	Enable AIO ioengine
curl	Enable HTTP engine for S3 and WebDav support support via net-misc/curl
glusterfs	Enable GlusterFS gfapi support via sys-cluster/glusterfs
gnuplot	Install tools for generating gnuplots
io-uring	Enable efficient I/O via sys-libs/liburing.
nfs	Enable NFS support
numa	Enable numa support
pandas	Install dependencies for complex python scripts
rbd	Enable Rados block device support via sys-cluster/ceph
rdma	Enable infiniband support via sys-cluster/rdma-core
tcmalloc	Link against dev-util/google-perftools by default which will speed up USE=rbd up to 20%
zbc	Enable ZBC & ZAC disks via sys-block/libzbc.

gparted

wayland	Enable interim workaround to allow running GParted under Wayland by granting permission to the X11 display using x11-apps/xhost

libfabric

efa	Enable Amazon EC2 Elastic Fabric Adapter provider
rocr	Enable Radeon Open Compute provider
usnic	Enable Cisco VIC (virtualized NIC) hardware on Cisco UCS server provider
verbs	Enable Linux Infiniband verbs provider

nbd

netlink	Add support for netlink protocol via dev-libs/libnl

nbdkit

ext2	Enable the ext2 filter via sys-fs/e2fsprogs.
libguestfs	Enable the app-emulation/libguestfs plugin.
libssh	Enable the SSH plugin via net-libs/libssh.
libvirt	Enable the app-emulation/libvirt plugin.
nbd	Enable the nbd plugin via sys-libs/libnbd.
torrent	Enable the torrent plugin via net-libs/libtorrent-rasterbar.
zlib-ng	Use sys-libs/zlib-ng to handle zlib decompression.

ndctl

libtracefs	Use dev-libs/libtracefs to build cxl-monitor binary

open-iscsi

rdma	Support iSCSI over RDMA
tcp	Support iSCSI over TCP

parted

debug	Enable debugging as encouraged by upstream: [The default configuration] includes --enable-debug (by default), which contains many assertions. Obviously, these "waste" space, but in the past, they have caught potentially dangerous bugs before they would have done damage, so we think it's worth it. Also, it means we get more bug reports ;)
device-mapper	Enable device-mapper support from sys-fs/lvm2 in parted

partimage

nologin	Do not include login support when connecting partimaged

perccli

uefi	Install UEFI variant as well

sas2ircu

uefi	Install UEFI variant as well

sas3flash

uefi	Install UEFI variant as well

sas3ircu

uefi	Install EFI variant as well

tgt

rbd	Add support for ceph block devices

thin-provisioning-tools

io-uring	Enable experimental support for io-uring.

sys-boot

grub

device-mapper	Enable support for devmapper. Required for LUKS or LVM volume detection.
efiemu	Build and install the efiemu runtimes
fonts	Build and install fonts for the gfxterm module
libzfs	Enable support for sys-fs/zfs
mount	Build and install the grub-mount utility
themes	Build and install GRUB themes (starfield)
truetype	Build and install grub-mkfont conversion utility

lilo

device-mapper	Enable support for device-mapper from sys-fs/lvm2
minimal	Do not install the dolilo helper script
pxeserial	Avoid character echo on PXE serial console

plymouth

drm	Provides abstraction to the DRM drivers (intel, nouveau and vmwgfx at this moment)
freetype	Build with freetype support (if enabled, used for encryption prompts)
pango	Adds support for printing text on splash screen and text prompts, e.g. for password
split-usr	Enable this if /bin and /usr/bin are separate directories

refind

btrfs	Builds the EFI binary btrfs filesystem driver
ext2	Builds the EFI binary ext2 filesystem driver
ext4	Builds the EFI binary ext4 filesystem driver
hfs	Builds the EFI binary hfs filesystem driver
iso9660	Builds the EFI binary iso9660 filesystem driver
ntfs	Builds the EFI binary ntfs filesystem driver
reiserfs	Builds the EFI binary reiserfs filesystem driver

silo

tilo-only	Install only the tilo netboot tool

syslinux

bios	Enable BIOS support
uefi	Enable UEFI support

vboot-utils

libzip	Use dev-libs/libzip.

sys-cluster

ceph

babeltrace	Add support for LTTng babeltrace
cephfs	Build support for cephfs, a POSIX compatible filesystem built on top of ceph
diskprediction	Enable local diskprediction module to predict disk failures
dpdk	Enable DPDK messaging
fuse	Build fuse client
grafana	Install grafana dashboards
jaeger	Enable jaegertracing and it's dependent libraries
kafka	Rados Gateway's pubsub support for Kafka push endpoint
lttng	Add support for LTTng
mgr	Build the ceph-mgr daemon
parquet	Support for s3 select on parquet objects
pmdk	Enable PMDK libraries
rabbitmq	Use rabbitmq-c to build rgw amqp push endpoint
radosgw	Add radosgw support
rbd-rwl	Enable librbd persistent write back cache
rbd-ssd	Enable librbd persistent write back cache for SSDs
rdma	Enable RDMA support via sys-cluster/rdma-core
rgw-lua	Rados Gateway's support for dynamically adding lua packagess
spdk	Enable SPDK user-mode storage driver toolkit
system-boost	Use system dev-libs/boost instead of the bundled one
uring	Build with support for sys-libs/liburing
xfs	Add xfs support
zbd	Enable sys-block/libzbd bluestore backend

charliecloud

ch-image	Build the internal builder ch-image (previously named ch-grow)

charm

ampi	Build implementation of MPI on top of Charm++
charmdebug	Enable the charm debugger
charmproduction	Optimize performance of Charm++ runtime
charmtracing	Enable tracing support in Charm++
cmkopt	Enable CMK optimisation
mlogft	Compile with Charm++ message logging fault tolerance support
numa	Support memory affinity with NUMA
syncft	Compile with Charm++ fault tolerance support
tcp	Use TCP (instead of UPD) for socket communication

cluster-glue

ipmilan	Install the ipmilan plugin (requires sys-libs/openipmi)
libnet	Force use of net-libs/libnet

corosync

augeas	Enable augeas support
watchdog	Enable watchdog support

drbd-utils

pacemaker	Enable Pacemaker integration
xen	Enable Xen integration

galera

garbd	Install Galera Arbitrator - a stateless daemon which acts as a lightweight group member

glusterfs

fuse	Add FUSE mount helper
georeplication	Enable support for georeplication (requires dev-lang/python)
ipv6	Use IPv6 by default, requires libtirpc
libtirpc	Build against net-libs/libtirpc for RPC support
rsyslog	Install configuration snippet for app-admin/rsyslog
uring	Control whether or not glusterfs is compiled with uring support or not.

hpx

papi	Use dev-libs/papi for NaCl
perftools	Use dev-util/google-perftools for memory allocation
tbb	Use dev-cpp/tbb for memory allocation

k3s

kubectl-symlink	Install a kubectl symlink that points to k3s.
rootless	Enables dependencies for running in rootless mode.

keepalived

bfd	compile with support for Bidirectional Forwarding Detection (BFD).
json	compile with signal to dump configuration and stats as JSON.
regex	compile with support for regex in health checks

kronosnet

lzo2	Add support for lzo2 compression
nss	Add support for tls via nss
openssl	Add support for tls via openssl

legion

gasnet	Enable GASNet lib support
hwloc	Enable HWLoc lib support

lmod

auto-swap	enable auto swapping of compiler
cache	enable caching of modules
duplicate-paths	allow duplicate entries in path

minikube

libvirt	Build plugin for kvm

mpich

mpi-threads	Enable MPI_THREAD_MULTIPLE
romio	Build the ROMIO MPI-IO component

nomad

ui	do not embed the ui in the binary

openmpi

cma	Enable the CMA (Cross Memory Attach) MCA
libompitrace	Enable support for contributed package libompitrace
peruse	Enable PERUSE interface
romio	Build the ROMIO MPI-IO component

pacemaker

smtp	Enable SMTP support via net-libs/libesmtp

pmix

munge	Enable authentication via munge
pmi	Build PMI1 and PMI2 interface

rdma-core

lttng	Enable support for the LTTng tracer
neigh	Enable iwpmd support
python	Enable pyverbs support

resource-agents

libnet	Force use of net-libs/libnet
rgmanager	Install resources for rgmanager

slurm

html	Build html documentation
ipmi	Build support for collecting some ipmi stats
json	Add support for json-persing via json-c
multiple-slurmd	Allow multiple slurmd to run
munge	Enable authentication via munge
numa	Add NUMA awareness
nvml	Enable the NVML device discovery
ofed	Add Infiniband support via ofed
slurmdbd	Install SQL server for slurmdbd
slurmrestd	Enable interface to Slurm via REST API
torque	Enable perl scripts that emulates pbs (qstat, qsub etc.)
ucx	Enable Unified Communication X library support
yaml	Enable YAML support

torque

autorun	Enable the AUTORUN_JOBS codebase
cgroups	Enable pbs_mom to use linux cgroups to isolate jobs
cpusets	Enable pbs_mom to utilize linux cpusets if available
munge	Enable authentication via munge
nvidia	Enable management of Nvidia GPUs
quickcommit	Enable the QUICKCOMMIT codebase
server	Enable compilation of pbs_server and pbs_sched

ucx

numa	Add support for numa memory allocation

vzctl

ploop	Add support for ploop devices via sys-cluster/ploop
vzmigrate	Add support for container migration

sys-devel

autogen

libopts	install the libopts tarball (a few packages want this for developing)

binutils

cet	Enable Intel Control-flow Enforcement Technology.
debuginfod	Enable debuginfod support via dev-libs/elfutils libdebuginfod
default-gold	Set ld to point to ld.gold instead of ld.bfd
gold	Build ld.gold linker
gprofng	Enable the next-generation gprofng profiler
multitarget	Adds support to binutils for cross compiling (does not work with gas)
pgo	Build binutils with Profile Guided Optimization (PGO) and LTO
plugins	Enable plugin support in tools

binutils-apple

classic	Use nm, otool, etc. from this ebuild instead of llvm-based tools
lto	Add support for Link-Time Optimization with LLVM

binutils-config

native-symlinks	Install native symlinks like 'as' or 'ar' to /usr/bin. Otherwise keep only ${CTARGET}-as and friends.

binutils-hppa64

cet	Enable Intel Control-flow Enforcement Technology.
debuginfod	Enable debuginfod support via dev-libs/elfutils libdebuginfod
default-gold	Set ld to point to ld.gold instead of ld.bfd
gold	Build ld.gold linker
gprofng	Enable the next-generation gprofng profiler
multitarget	Adds support to binutils for cross compiling (does not work with gas)
pgo	Build binutils with Profile Guided Optimization (PGO) and LTO
plugins	Enable plugin support in tools

bpf-toolchain

bin-symlinks	Symlink executables to usr/bin to be in default PATH (conflicts with crossdev bpf, and crossdev is preferable for a fully featured toolchain)

clang

extra	Build extra tools (clangd, clang-tidy and a few more)
ieee-long-double	Use accelerated 128-bit IEEE long double ABI (ppc64le only)
static-analyzer	Install the Clang static analyzer

clang-common

bootstrap-prefix	!!internal use only!! DO NOT SET THIS FLAG YOURSELF!, used for bootstrapping Gentoo Prefix
cet	Enable support for control flow hijacking protection. On amd64, this provides Intel Control Flow Enforcement Technology (CET). Only provides benefits on newer CPUs. For Intel, the CPU must be at least as new as Tiger Lake. For AMD, it must be at least as new as Zen 3. This is harmless on older CPUs, but provides no benefit either.
default-compiler-rt	Use compiler-rt + libunwind instead of libgcc as the default rtlib for clang
default-libcxx	Use libc++ instead of libstdc++ as the default stdlib for clang
default-lld	Use lld as the default linker for clang
stricter	Default to stricter behavior known from newer clang versions, turning more warnings into errors

clang-runtime

compiler-rt	Install sys-libs/compiler-rt for -rtlib=compiler-rt
libcxx	Install sys-libs/libcxx for -stdlib=libc++
openmp	Install sys-libs/libomp for -fopenmp support
sanitize	Enable compiler-rt sanitizer (-fsanitize*) support

clang-toolchain-symlinks

gcc-symlinks	Install symlinks for 'gcc' and 'g++' for extra compatibility.
multilib-symlinks	Install symlinks for all ABI CHOSTs. Note that this can result in gcc being overrode for native builds, as well as conflict with crossdev if used for the same targets.
native-symlinks	Install generic tool symlinks like 'cc' and 'c++', as well as ${CTARGET}-*. These symlinks are installed into slotted LLVM bindir, so they should not take precedence over symlinks installed into /usr/bin by sys-devel/gcc-config but they can be helpful for GCC-free setups.

crosstool-ng

dtc	Require sys-apps/dtc
lzip	Require app-arch/lzip
meson	Require dev-build/meson
ninja	Require app-alternatives/ninja
rsync	Require net-misc/rsync
wget	Require net-misc/wget

distcc

gssapi	Enable support for net-libs/libgssglue

gcc

ada	Build the ADA language (GNAT) frontend
cet	Enable support for control flow hijacking protection. On amd64, this provides Intel Control Flow Enforcement Technology (CET). On arm64, this provides Branch Target Identification (BTI) and Pointer Authentication Code (PAC) support. This is only effective on amd64 or arm64. Only provides benefits on newer CPUs. For Intel, the CPU must be at least as new as Tiger Lake. For AMD, it must be at least as new as Zen 3. This is harmless on older CPUs, but provides no benefit either. For ARM64, PAC was introduced in armv8.3-a, and BTI was introduced in armv8.5-a. When combined with USE=hardened on amd64, GCC will set -fcf-protection by default when building software. The effect is minimal on systems which do not support it, other than a possible small increase in codesize for the NOPs. The generated code is therefore compatible with i686 at the earliest. On arm64, GCC will set -mbranch-protection=standard by default when building software.
d	Enable support for the D programming language
debug	Enables GCC's 'checking' facility via --enable-checking=yes,extra,rtl. This adds checks to various compiler passes for integrity and input validation. This can help catch possible miscompilations early as well as latent bugs which could become real problems in future, but at the cost of slower compile times when using GCC. Unrelated to backtraces.
default-stack-clash-protection	Build packages with stack clash protection on by default as a hardening measure. This enables -fstack-clash-protection by default which protects against large memory allocations allowing stack smashing. May cause slightly increased codesize, but modern compilers have been adapted to optimize well for this case, as this mitigation is now quite common. See https://developers.redhat.com/blog/2020/05/22/stack-clash-mitigation-in-gcc-part-3 and https://www.qualys.com/2017/06/19/stack-clash/stack-clash.txt.
default-znow	Request full relocation on start from ld.so by default. This sets the -z,now (BIND_NOW) flag by default on all linker invocations. By resolving all dynamic symbols at application startup, parts of the program can be made read-only as a hardening measure. This is closely related to RELRO which is also separately enabled by default. In some applications with many unresolved symbols (heavily plugin based, for example), startup time may be impacted.
fixed-point	Enable fixed-point arithmetic support for MIPS targets in gcc (Warning: significantly increases compile time!)
go	Build the GCC Go language frontend.
graphite	Add support for the framework for loop optimizations based on a polyhedral intermediate representation
ieee-long-double	Use accelerated 128-bit IEEE long double ABI (ppc64le only)
jit	Enable libgccjit so other applications can embed gcc for Just-In-Time compilation.
libdiagnostics	Provide libdiagnostics (https://gcc.gnu.org/wiki/libdiagnostics). This also installs the 'sarif-replay' tool.
libssp	Build SSP support into a dedicated library rather than use the code in the C library (DO NOT ENABLE THIS IF YOU DON'T KNOW WHAT IT DOES)
lto	Build using Link Time Optimizations (LTO). Note that GCC is always built with support for building other programs with LTO. This USE flag is for whether GCC itself is built and optimized with LTO.
modula2	Build the GCC Modula-2 language frontend.
objc	Build support for the Objective C code language
objc++	Build support for the Objective C++ language
objc-gc	Build support for the Objective C code language Garbage Collector
pgo	Build GCC using Profile Guided Optimization (PGO). GCC will build itself and then analyze the just-built binary and then rebuild itself using the data obtained from analysis of codepaths taken. It does not affect whether GCC itself supports PGO when building other software. This substantially increases the build time needed for building GCC itself.
rust	Build support for the Rust language, installs gccrs.
sanitize	Build support for various sanitizer functions (ASAN/TSAN/etc...) to find runtime problems in applications.
ssp	Build packages with stack smashing protection on by default
systemtap	enable systemtap static probe points
vtv	Build support for virtual table verification (a C++ hardening feature). This does not control whether GCC defaults to using VTV> Note that actually using VTV breaks ABI and hence the whole system must be built with -fvtable-verify.

gcc-apple

bootstrap	!DO NOT SET THIS FLAG YOURSELF! avoids need for autoconf during bootstrap stage2
objc	Build support for the Objective C code language
objc++	Build support for the Objective C++ language

gcc-config

cc-wrappers	Install and manage 'cc' and 'f77' wrappers in /usr/bin. Otherwise ignore them.
native-symlinks	Install native symlinks like 'gcc' or 'g++' to /usr/bin. Otherwise keep only ${CTARGET}-gcc and friends.

gettext

git	When running `autopoint`, use git to store the internal development files; this requires git at runtime, but will be faster/smaller than raw archives

lld-toolchain-symlinks

multilib-symlinks	Install symlinks for all ABI CHOSTs. Note that this can result in gcc being overrode for native builds, as well as conflict with crossdev if used for the same targets.
native-symlinks	Install generic 'ld' symlink, as well as ${CTARGET}-ld. These symlinks are installed into slotted LLVM bindir, so they should not take precedence over symlinks installed into /usr/bin by sys-devel/binutils-config but they can be helpful for binutils-free setups.

llvm

binutils-plugin	Build the binutils plugin
debuginfod	Install llvm-debuginfod (requires net-misc/curl and dev-cpp/cpp-httplib)
doc	Build and install the HTML documentation and regenerate the man pages
exegesis	Enable performance counter support for llvm-exegesis tool that can be used to measure host machine instruction characteristics
ncurses	Support querying terminal properties using ncurses' terminfo
xar	Support dumping LLVM bitcode sections in Mach-O files (uses app-arch/xar)
z3	Enable support for sci-mathematics/z3 constraint solver

llvm-toolchain-symlinks

multilib-symlinks	Install symlinks for all ABI CHOSTs. Note that this can result in gcc being overrode for native builds, as well as conflict with crossdev if used for the same targets.
native-symlinks	Install generic tool symlinks like 'objdump' and 'ranlib', as well as ${CTARGET}-*. These symlinks are installed into slotted LLVM bindir, so they should not take precedence over symlinks installed into /usr/bin by sys-devel/binutils-config but they can be helpful for binutils-free setups.

sparse

gtk	Build the test-inspect utility (requires x11-libs/gtk+:3)
llvm	Build the sparse-llvm utility
xml	Build the c2xml utility (requires dev-libs/libxml2)

sys-fabric

mstflint

adb-generic-tools	Enable compiling the following tools: mstreg and mstlink
inband	Enable firmware updates for Mellanox SwitchX and ConnectIB devices

opensm

tools	Install ssld extra tool

sys-firmware

broadcom-bt-firmware

compress-xz	Compress firmware using xz (app-arch/xz-utils) before installation
compress-zstd	Compress firmware using zstd (app-arch/zstd) before installation

intel-microcode

hostonly	Only install ucode(s) supported by currently available (=online) processor(s)
initramfs	Install a small initramfs for use with CONFIG_MICROCODE_EARLY
split-ucode	Install the split binary ucode files (used by the kernel directly)
vanilla	Only install microcode updates from Intel's official microcode tarball

ipxe

binary	Use pre-built binaries
iso	Build a bootable ISO for using PXE
lkrn	Build a linux kernel bootable file for using with grub/etc...
qemu	Build the required PXE ROM images for app-emulation/qemu
uefi32	Build a 32bit UEFI program for using PXE
uefi64	Build a 64bit UEFI program for using PXE
undi	Build a Universal Network Device Interface driver chainloading your existing PXE NIC into iPXE
usb	Build a bootable USB image for using PXE
vmware	Build the PXE ROM images that VMWare uses

seabios

binary	Use official upstream pre-built binaries
seavgabios	Include SeaVGABIOS binaries (replacement for vgabios)

sgabios

binary	Use pre-built binaries

sigrok-firmware-fx2lafw

binary	Use official upstream pre-built binaries

sof-firmware

tools	Tools to interact with sof firmwares (upstream expects them to be present, but allow to skip them for systems not able to install needed dependencies)

vgabios

binary	Use official upstream pre-built binaries (only default and cirrus images)

sys-fs

android-file-transfer-linux

fuse	Add FUSE mount helper
zune	Enable support for Microsoft Zune

avfs

webdav	Allow mounting WebDAV shares via net-libs/neon

bcachefs-tools

fuse	Enable bcachefs FUSE support (experimental!)

btrfs-progs

convert	Build ext2 conversion utility (btrfs-convert)
experimental	Enable unstable and experimental features and install btrfs-corrupt-block, as needed by xfstests
reiserfs	Enable reiserfs support in btrfs-convert tool.
static	Build static binaries in addition to the dynamic ones

btrfsmaintenance

systemd	Enable systemd services and timers instead of cron timers

cryptmount

argv0switch	Default action given by progname.
cswap	Enable support for encrypted swap.
fsck	Check filesystems before mounting.
gcrypt	Support libgcrypt-encryption of keys.
largefile	Enable support for large files.
luks	Enable key management via LUKS
mount	Use systemd mount/umount for operations.
openssl	Support openssl-encryption of keys.

cryptsetup

argon2	Enable password hashing algorithm from app-crypt/argon2
fips	Enable FIPS mode restrictions
gcrypt	Use dev-libs/libgcrypt crypto backend
kernel	Use kernel crypto backend (mainly for embedded systems)
nettle	Use dev-libs/nettle crypto backend
openssl	Use dev-libs/openssl crypto backend
pwquality	Use dev-libs/libpwquality for password quality checking
ssh	Build cryptsetup-ssh for experimental support of token via SSH-server
urandom	Use /dev/urandom instead of /dev/random

dmraid

intel-led	Enable Intel LED support
led	Enable LED support
mini	Create a minimal binary suitable for early boot environments

dosfstools

compat	Install symlinks for legacy names of the tools

e2fsprogs

archive	Add support for mke2fs to read a tarball as input. This allows not needing privileges. Needs app-arch/libarchive.
cron	Install e2scrub_all cron script
fuse	Build fuse2fs, a FUSE file system client for ext2/ext3/ext4 file systems
tools	Build extfs tools (mke2fs, e2fsck, tune2fs, etc.)

ecryptfs-utils

gpg	Enable app-crypt/gnupg key module
openssl	Enable dev-libs/openssl key module
pkcs11	Enable PKCS#11 (Smartcards) key module
tpm	Enable support for Trusted Platform Module (TPM) using app-crypt/trousers

erofs-utils

fuse	Builds erofsfuse (requires sys-fs/fuse).
libdeflate	Use app-arch/libdeflate rather than sys-libs/zlib for handling deflate compression.
uuid	Enables UUID support via sys-apps/util-linux.

ext4magic

expert-mode	Builds ext4magic with expert mode. Highly useful in recovering data from a corrupted filesystem
file-attr	Enable the recovery of file attributes (append, immutable, nodump etc)

lessfs

filelog	Enable the ability to log to a file instead of syslog
memtrace	Enable leefs to create a report regarding the memory allocation. This feature should be used for debugging purposes to avoid performance degradation

loop-aes

extra-ciphers	Enable extra ciphers
keyscrub	Protects the encryption key in memory but takes more cpu resources

lvm2

lvm	Build all of LVM2 including daemons and tools like lvchange, not just the device-mapper library (for other packages to use). If your system uses LVM2 for managing disks and partitions, enable this flag.
sanlock	Enable lvmlockd with support for sanlock
thin	Support for thin volumes

mdadm

corosync	Support for corosync cluster engine

mtd-utils

ubifs	Build UBIFS tools

mtpfs

mad	Enable handling of MP3's metadata

ntfs3g

fuse	Enable ntfs-3g FUSE driver
mount-ntfs	Install mount.ntfs symlink
ntfsdecrypt	Build and install the ntfsdecrypt application.
ntfsprogs	Enable ntfsprogs

quota

netlink	Compile daemon receiving quota messages via netlink
rpc	Enable quota interaction via RPC

squashfs-tools-ng

tools	Build the gensquashfs, rdsquashfs, sqfs2tar, sqfsdiff, and tar2sqfs tools

udisks

daemon	Build the system daemon, not just the client tool
elogind	Use sys-auth/elogind for session tracking
lvm	Add support for Logical Volume Management via sys-fs/lvm2.
systemd	Support sys-apps/systemd's logind
vdo	Enable Virtual Data Optimizer support.
zram	Enable ZRAM support (requires sys-apps/systemd).

zfs

kernel-builtin	Disable dependency on sys-fs/zfs-kmod under the assumption that ZFS is part of the kernel source tree
minimal	Don't install python scripts (arcstat, dbufstat etc) and avoid dependency on dev-lang/python
pam	Install zfs_key pam module, for automatically loading zfs encryption keys for home datasets
rootfs	Enable dependencies required for booting off a pool containing a rootfs
test-suite	Install regression test suite

zfs-auto-snapshot

cron	Install /etc/cron.* files
default-exclude	Only take snapshots of datasets with com.sun:auto-snapshot=true property set

zfs-kmod

dist-kernel-cap	Prevents upgrading to an unsupported kernel version when combined with USE=dist-kernel
rootfs	Pull dependencies and check kernel options required for root-on-zfs

sys-kernel

asahi-sources

symlink	Automatically symlink the kernel sources to /usr/src/linux

dracut

dracut-cpio	Build the enhanced 'dracut-cpio' program

genkernel

firmware	Prefer system firmware sys-kernel/linux-firmware over local copy.

gentoo-kernel

experimental	Apply experimental patches; for more information, see "https://wiki.gentoo.org/wiki/Project:Kernel/Experimental".
generic-uki	Build and install a generic initramfs and Unified Kernel Image, this is intended for building binpkgs with a pre-generated UKI included (EXPERIMENTAL).
hardened	Use selection of hardening options recommended by Kernel Self Protection Project
initramfs	Build initramfs along with the kernel.

gentoo-kernel-bin

generic-uki	Install a prebuilt generic initramfs and Unified Kernel Image (EXPERIMENTAL).
initramfs	Build initramfs along with the kernel.

gentoo-sources

experimental	Apply experimental patches; for more information, see "https://wiki.gentoo.org/wiki/Project:Kernel/Experimental".

installkernel

dracut	Generate an initramfs or UKI on each kernel installation
efistub	EXPERIMENTAL: Update UEFI configuration on each kernel installation
grub	Re-generate grub.cfg on each kernel installation, used grub.cfg is overridable with GRUB_CFG env var
refind	Install a Gentoo icon for rEFInd alongside the (unified) kernel image, used icon is overridable with REFIND_ICON env var
systemd	Use systemd's kernel-install to install kernels, overridable with SYSTEMD_KERNEL_INSTALL env var
systemd-boot	Use systemd-boot's native layout by default
ugrd	Generate an initramfs using UGRD on each kernel installation
uki	Install UKIs to ESP/EFI/Linux for EFI stub booting and/or bootloaders with support for auto-discovering UKIs
ukify	Build an UKI with systemd's ukify on each kernel installation

kpatch

contrib	Enable contrib kpatch services files.
kmod	Enable a kernel module (.ko file) which provides an interface for the patch modules to register new functions for replacement.
kpatch	Enable a command-line tool which allows a user to manage a collection of patch modules.
kpatch-build	Enable tools which convert a source diff patch to a patch module.

linux-firmware

compress-xz	Compress firmware using xz (app-arch/xz-utils) before installation
compress-zstd	Compress firmware using zstd (app-arch/zstd) before installation
deduplicate	Create symlinks for all firmware that is duplicate using rdfind
initramfs	Create and install initramfs for early microcode loading in /boot (only AMD for now)
redistributable	Install also non-free (but redistributable) firmware files
savedconfig	Allows individual selection of firmware files
unknown-license	Install firmware files whose license is unknown

mips-sources

experimental	Apply experimental (80xx) patches.
ip27	Enables additional support for SGI Origin (IP27)
ip28	Enables additional support for SGI Indigo2 Impact R10000 (IP28)
ip30	Enables support for SGI Octane (IP30, 'Speedracer')

rt-sources

deblob	Remove binary blobs from kernel sources to provide libre license compliance.

scx

openrc	Enable support for sys-apps/openrc

vanilla-kernel

initramfs	Build initramfs along with the kernel.

sys-libs

binutils-libs

64-bit-bfd	Support 64-bit targets even on 32-bit hosts (is ignored on 64-bit hosts)
cet	Enable Intel Control-flow Enforcement Technology.
multitarget	Enable all possible targets in libbfd

compiler-rt

atomic-builtins	Compile atomic builtins into compiler-rt.builtins. This is needed on systems without GCC/libatomic, but requires using Clang to build.
clang	Force building using installed clang (rather than the default CC/CXX).

compiler-rt-sanitizers

asan	Build Address Sanitizer runtime.
cfi	Build Control Flow Integrity runtime.
clang	Force building using installed clang (rather than the default CC/CXX).
ctx-profile	Build ctx profiling runtime.
dfsan	Build Data Flow Sanitizer runtime.
gwp-asan	Build GWP-ASAN runtime.
hwasan	Build Hardware ASAN runtime.
libfuzzer	Build fuzzing runtime.
lsan	Build Leak Sanitizer runtime.
memprof	Build memory profiler runtime.
msan	Build Memory Sanitizer runtime.
nsan	Build Numerical Sanitizer runtime.
orc	Build ORC runtime.
profile	Build profiling runtime.
rtsan	Build Realtime Sanitizer runtime.
safestack	Build SafeStack runtime.
scudo	Build Scudo Hardened Allocator.
shadowcallstack	Build ShadowCallStack.
tsan	Build Thread Sanitizer runtime.
ubsan	Build Undefined Behavior Sanitizer runtime.
xray	Build XRay runtime.

freeipmi

nagios	Install a nagios plugin to check sensors' status.
without-root	Configure whether or not to check for root access in ipmi tools.

gdbm

berkdb	enable compatibility layer for UNIX-like dbm and ndbm interfaces

glibc

cet	Enable Intel Control-flow Enforcement Technology (needs binutils 2.29 and gcc 8)
clone3	Enable the new clone3 syscall within glibc. Can be disabled to allow compatibility with older Electron applications.
compile-locales	build *all* locales in src_install; this is generally meant for stage building only as it ignores /etc/locale.gen file and can be pretty slow
crypt	build and install libcrypt and crypt.h
debug	When USE=hardened, allow fortify/stack violations to dump core (SIGABRT) and not kill self (SIGKILL)
experimental-loong	Add experimental LoongArch patchset
gd	build memusage and memusagestat tools
hash-sysv-compat	enable sysv linker hashes in glibc for compatibility with binary software (EAC via wine/proton)
multiarch	enable optimizations for multiple CPU architectures (detected at runtime)
multilib-bootstrap	Provide prebuilt libgcc.a and crt files if missing. Only needed for ABI switch.
nscd	Build, and enable support for, the Name Service Cache Daemon
perl	Install additional scripts written in Perl
ssp	protect stack of glibc internals
stack-realign	Realign the stack in the 32-bit build for compatibility with older binaries at some performance cost
static-pie	Enable static PIE support (runtime files for -static-pie gcc option).
suid	Make internal pt_chown helper setuid -- not needed if using Linux and have /dev/pts mounted with gid=5
systemtap	enable systemtap static probe points

ldb

doc	Builds documentation
ldap	Enable LDAP support
lmdb	Enable LMDB backend
python	Enable Python support

libblockdev

bcache	Enable block device cache support.
cryptsetup	Enable sys-fs/cryptsetup support
device-mapper	Enable support for device-mapper from sys-fs/lvm2
dmraid	Support for dmraid devices, also known as ATA-RAID, or Fake RAID.
escrow	Support for building crypto plugin with escrow device support
kbd	Enable kernel block device support.
lvm	Enable support for Logical Volume Management via sys-fs/lvm2.
nvme	Add nvme support via sys-libs/libnvme
tools	Build tools
vdo	Enable Virtual Data Optimizer support.

libcap

tools	Install captree, which requires dev-lang/go

libcxx

clang	Force building using installed clang (rather than the default CC/CXX; required for testing).
libcxxabi	Build on top of sys-libs/libcxxabi instead of gcc's libsupc++ (avoids depending on gcc).

libcxxabi

clang	Force building using installed clang (rather than the default CC/CXX; required for testing).

libnbd

fuse	Install the sys-fs/fuse powered nbdfuse.
go	Build bindings for dev-lang/go
uri-support	Enable nbd:// URI support via dev-libs/libxml2.

libnvme

json	Support JSON output via dev-libs/json-c
keyutils	Add support for sys-apps/keyutils
uuid	UUID support via sys-apps/util-linux

libomp

gdb-plugin	Build OMPD GDB plugin
hwloc	Enable CPU affinity support via hwloc
offload	Support offloading OpenMP using libomptarget
ompt	Enable OpenMP Tools Interface support

libseccomp

experimental-loong	Add experimental LoongArch patchset

libunwind

debug-frame	Adds support for DWARF .debug_frame section: Use the information from this section if available
libatomic	Use libatomic instead of builtin atomic operations

libxcrypt

compat	Build with compatibility interfaces for other crypt implementations
headers-only	Build and install only the headers.
system	Install as system libcrypt.so rather than to an alternate directory (will collide with sys-libs/glibc's version)

llvm-libunwind

clang	Force building using installed clang (rather than the default CC/CXX; required for testing).

minizip-ng

compat	Enable compatibility with sys-libs/zlib's USE=minizip
openssl	Use dev-libs/openssl for further encryption capabilities

musl-nscd

minimal	Only installs the header files

ncurses

ada	Add bindings for the ADA programming language
stack-realign	Realign the stack in the 32-bit build for compatibility with older binaries at some performance cost. Avoids crashes in older 32-bit binaries. Only affects x86/32-bit multilib builds on amd64.
tinfo	Build curses library (libncurses) sep from the low-level terminfo library (libtinfo) -- usually needed only for binary packages -- but it is binary compatible in either mode
trace	Enable test trace() support in ncurses calls

ncurses-compat

stack-realign	Realign the stack in the 32-bit build for compatibility with older binaries at some performance cost. Avoids crashes in older 32-bit binaries. Only affects x86/32-bit multilib builds on amd64.
tinfo	Build curses library (libncurses) sep from the low-level terminfo library (libtinfo) -- usually needed only for binary packages -- but it is binary compatible in either mode

newlib

nano	Build additional newlib-nano library

pam

berkdb	Build the pam_userdb module, that allows to authenticate users against a Berkeley DB file. Please note that enabling this USE flag will create a PAM module that links to the Berkeley DB (as provided by sys-libs/db) installed in /usr/lib and will thus not work for boot-critical services authentication.

readline

utils	Install rlfe (ReadLine Front-End) helper tool -- a wrapper program for making any stdin use readline

snapd-glib

qml	Build the QML bindings

talloc

compat	Enable extra compatibility stuff

timezone-data

leaps-timezone	Install the set of "right" timezones; these timezones include leap seconds when counting seconds since the epoch (while POSIX does not) as they are based on the TAI (International Atomic Time) clock
zic-slim	Default to 'slim' file format for /usr/share/zoneinfo. Otherwise 'fat' format is used. Not all programs can handle 'slim' format'.

zlib

minizip	include the minizip library for quick and dirty zip extraction

zlib-ng

compat	Enable compatibility to sys-libs/zlib

sys-power

apcupsd

modbus	Enable MODBUS support over USB

autosuspend

mpd	Enable support for the Music Player Daemon

intel-undervolt

elogind	Use elogind hook to apply voltage after system sleep

nut

gpio	Includes all UPS drivers that use GPIO.
i2c	Includes all UPS drivers that use I2C.
ipmi	Includes all UPS drivers that use ipmi.
modbus	Includes all UPS drivers that use MODBUS.
monitor	Add a QT5 gui monitor.
serial	Includes all UPS drivers that use SERIAL.
snmp	Includes all UPS drivers that use SNMP.
usb	Includes all UPS drivers that use USB.
xml	Includes all UPS drivers that use XML.

nvclock

gtk	Install the GTK+ based graphical interface
nvcontrol	Add NVCONTROL support for OpenGL options

suspend

crypt	Allows suspend and resume from encrypted disk

sys-process

atop

modules	Build netatop kernel module and install netatopd daemon.

audit

gssapi	Enable GSSAPI support
io-uring	Enable support for io-uring. Doesn't need the library but needs at least kernel 5.1.

bottom

battery	Include support for laptop battery information
gpu	Include support for GPU temperature and memory usage information
zfs	Include support for ZFS ARC memory usage information

criu

bpf	Add support for BPF programs via dev-libs/libbpf
filecaps	Install the criu binary with file capabilities to allow for rootless CRIU
nftables	Add support for net-firewall/nftables
setproctitle	Use dev-libs/libbsd to make process titles of service workers to be more verbose

cronie

anacron	Install the periodic anacron command scheduler.

fcron

debug	Enable debug code and output. Since version 3.0.5 this will no longer force foreground execution, and fcron will be able to run as a service properly.
mta	Enable mta support for sending emails from fcron
pam	Enable PAM support for fcron. This means that fcron will pass through the "fcron" stack before executing the jobs, and fcrontab will use the "fcrontab" stack to authenticate the user before editing its crontab file.
system-crontab	Set up fcron to respect /etc/crontab and /etc/cron.d. If this flag is disabled, /etc/cron.d and /etc/crontab will be ignored, but /etc/cron.{hourly,daily,weekly,monthly} will still be respected. Also this creates /usr/bin/crontab symlink.

htop

delayacct	Enable Linux delay accounting support via dev-libs/libnl
hwloc	Use sys-apps/hwloc for CPU affinity support
openvz	Enable openvz support
vserver	Enable vserver support

lsof

rpc	support looking up RPC service info

procps

elogind	Use sys-auth/elogind for session tracking.
kill	Build the kill program
modern-top	Enables new startup defaults of top. Keeps old defaults if disabled
ncurses	Build programs that use ncurses: top, slabtop, watch

systemd-cron

cron-boot	Include support for the boot timer.
etc-crontab-systemd	Use dedicated /etc/crontab-systemd instead of parsing /etc/crontab
minutely	Support /etc/cron.minutely
runparts	Use traditional run-parts instead of creating jobs for each cron.* entry
setgid	Compile setgid C helper for crontab. Needs GCC or Clang.
yearly	Support /etc/cron.yearly

tini

args	Enable argument parsing.

virtual

blas

eselect-ldso	Enable runtime library switching by eselect and ld.so.

cblas

eselect-ldso	Enable runtime library switching by eselect and ld.so.

jdk

headless-awt	Don't install the X backend for AWT, needed by some GUIs

lapack

eselect-ldso	Enable runtime library switching by eselect and ld.so.

lapacke

eselect-ldso	Enable runtime library switching by eselect and ld.so.

linux-sources

firmware	Install linux kernel firmware

mpi

nullmpi	Allow sys-cluster/nullmpi a minimal incomplete MPI implementation as a provider
romio	Enable romio, a high-performance portable MPI-IO

mysql

embedded	Build embedded server (libmysqld)
server	Build server (mysqld)

pkgconfig

native-symlinks	Install generic symlinks like pkgconf and pkg-config. If this flag is disabled, only CHOST-prefixed pkg-config executables will be available to end users and ebuilds.

podofo-build

boost	Add support for boost
tools	Build and install commandline tools

rust

profiler	Build the profiler runtime and rust-demangler tool (needed for '-C profile-generate' or '-C instrument-coverage' codegen opts)
rustfmt	Install rustfmt, Rust code formatter

ssh

minimal	Prefer net-misc/dropbear over net-misc/openssh

wine

proton	Enable Valve Software's fork of Wine
staging	Enable Wine-Staging's Patchset

www-apache

mod_auth_openidc

brotli	Add support for brotli compressed data using app-arch/brotli
redis	Add support for the Redis caching via dev-libs/hiredis

mod_backtrace

unwind	Use sys-libs/libunwind to provide better resolution of function names.

mod_musicindex

archive	Add archive support
cache	Add File cache support
mysql	Add MySQL cache support

mod_nss

ecc	enable Elliptical Curve Cyptography

mod_perl

ithreads	Build for use with thread-capable perl, needs same setting as in dev-lang/perl

mod_security

fuzzyhash	Support fuzzy hash computations (to detect malware, for example) using the app-crypt/ssdeep package.
geoip	Pull in dev-libs/geoip for use by the SecGeoLookupDb directive.
jit	Add support for the PCRE Just-in-Time optimisation, as enabled by dev-libs/libpcre with jit USE flag enabled. Might not be available on hardened systems.
json	Suppose JSON in the request body parser through dev-libs/yajl.
mlogc	Build and install the ModSecurity Audit Log Collector (mlogc).
pcre2	Use dev-libs/libpcre2 as regex implementation

pwauth

domain-aware	Ignore leading domain names in username (Windows compat)
faillog	Log failed login attempts
ignore-case	Ignore string case in username (mostly Windows compat)

www-apps

cgit

highlight	Enable source code highlighting
lua	Enable support for Lua scripting

drupal

uploadprogress	Install dev-php/pecl-uploadprogress package

gitea

acct	User and group management via acct-*/git packages
gogit	(EXPERIMENTAL) Use go-git variants of Git commands.

hugo

extended	Enable SASS/SCSS and WebP encoding support

icingaweb2

apache2-server	Adds support for the apache2-server
fpm	Adds FPM support to php
nginx	Adds support for nginx

ikiwiki

extras	Installs additional modules used by ikiwiki plugins

klaus

ctags	Enable support for Exuberant ctags; makes all source code symbols hyperlinks to their definitions

postfixadmin

vacation	Install vacation.pl script and dependencies

redmine

markdown	Enable support for Markdown
minimagick	Enable image processing support via dev-ruby/mini_magick
passenger	Enable support for www-apache/passenger
standalone	Enable standalone mode with www-servers/puma

roundup

jinja	Enable Jinja2 support
markdown	Enable markdown rendering
pyjwt	Enable jwt tokens for login
tz	Enable full support of timezone
whoosh	Enable Whoosh full-text indexer
xapian	Enable Xapian full-text indexer

rt

apache	Add www-servers/apache support
lighttpd	Add www-servers/lighttpd support
nginx	Add www-servers/nginx support

tt-rss

daemon	Install additional init scripts for automated RSS updates

ttyd

mbedtls	Use mbedTLS replacement for OpenSSL

webdavcgi

rcs	Adds support for a revision controlled backend with RCS (dev-vcs/rcs)

wordpress

akismet	Installs Akismet comment spam plug-in
themes	Installs themes (including default theme)

xpra-html5

brotli	Install assets compressed with brotli
gzip	Install assets compressed with gzip
minify	Minify JavaScript code for smaller transfers

www-client

chromium

debug	Enable DCHECK feature with severity configurable at runtime. Mostly intended for debugging and development, NOT RECOMMENDED for general use.
ffmpeg-chromium	(binpkg only) Use Chromium FFmpeg fork (media-video/ffmpeg-chromium) rather than mainline FFmpeg (media-video/ffmpeg)
gtk4	Build with GTK4 headers.
hangouts	Enable support for Google Hangouts features such as screen sharing
headless	Build Ozone only with headless backend, NOT RECOMMENDED for general use.
official	Enable Official build instead of Developer build.
pax-kernel	Allow building on a PaX-enabled kernel
pgo	Build with Profile Guided Optimizations (2-stage compilation)
proprietary-codecs	Enable codecs for patent-encumbered audio and video formats.
system-harfbuzz	Use system media-libs/harfbuzz instead of the bundled library.
system-icu	Use system dev-libs/icu instead of the bundled one
system-png	Use system media-libs/libpng instead of the bundled library
system-toolchain	Use system toolchain instead of the bundled one (if possible)
system-zstd	Use system app-arch/zstd instead of the bundled one.
widevine	Unsupported closed-source DRM capability (required by Netflix VOD)

dillo

mbedtls	Build against the net-libs/mbedtls library for TLS support.
openssl	Build against the dev-libs/openssl library for TLS support.
xembed	Enable XEmbed protocol support

elinks

bittorrent	Enable support for the BitTorrent protocol
finger	Enable support for the finger protocol
gemini	Enable support for the gemini protocol
gopher	Enable support for the gopher protocol
libcss	Enable support for cascading style sheets via dev-libs/libcss
mouse	Make elinks to grab all mouse events
tre	Enable support for regex searches via dev-libs/tre
xml	Enable support for bookmarks via dev-libs/expat

firefox

clang	Use Clang compiler instead of GCC
eme-free	Disable EME (DRM plugin) capability at build time
geckodriver	Enable WebDriver support
gmp-autoupdate	Allow Gecko Media Plugins (binary blobs) to be automatically downloaded and kept up-to-date in user profiles
gnome-shell	Integrate with gnome-base/gnome-shell search
hwaccel	Force-enable hardware-accelerated rendering (Mozilla bug 594876)
jumbo-build	Enable unified build - combines source files to speed up build process, but requires more memory
libproxy	Enable libproxy support
openh264	Use media-libs/openh264 for H264 support instead of downloading binary blob from Mozilla at runtime
pgo	Add support for profile-guided optimization for faster binaries - this option will double the compile time
pulseaudio	Add sound server support via media-libs/libpulse (may be PulseAudio or Pipewire, or apulse if installed)
sndio	Enable support for the media-sound/sndio backend
system-av1	Use the system-wide media-libs/dav1d and media-libs/libaom library instead of bundled
system-harfbuzz	Use the system-wide media-libs/harfbuzz instead of bundled and media-gfx/graphite2 in most cases
system-icu	Use the system-wide dev-libs/icu instead of bundled
system-jpeg	Use the system-wide media-libs/libjpeg-turbo instead of bundled
system-libevent	Use the system-wide dev-libs/libevent instead of bundled
system-libvpx	Use the system-wide media-libs/libvpx instead of bundled
system-png	Use the system-wide media-libs/libpng instead of bundled (requires APNG patches)
system-python-libs	Use system's python site instead of bundled python libraries
system-webp	Use the system-wide media-libs/libwebp instead of bundled
wasm	Sandbox certain third-party libraries through WebAssembly using RLBox
wifi	Enable necko-wifi for NetworkManager integration, and access point MAC address scanning for better precision with opt-in geolocation services

firefox-bin

alsa	When pulseaudio isn't set, this prefers apulse
gmp-autoupdate	Allow Gecko Media Plugins (binary blobs) to be automatically downloaded and kept up-to-date in user profiles

jd

migemo	Enable migemo support for Japanese
oniguruma	Use dev-libs/oniguruma for regular expression

links

freetype	Enable media-libs/freetype support
libevent	Enable dev-libs/libevent support

lynx

gnutls	Use gnutls library for HTTPS support (openssl is the default library for HTTPS support).
ssl	Enable HTTPS support.

microsoft-edge

mip	Install Microsoft Information Protection plugin.

microsoft-edge-beta

mip	Install Microsoft Information Protection plugin.

microsoft-edge-dev

mip	Install Microsoft Information Protection plugin.

netsurf

bmp	Bitmap (BMP and ICO) image support via media-libs/libnsbmp
gtk	Build GTK3 GUI
psl	Use public suffix list from media-libs/libnspsl to detect supercookies (recommended)
rosprite	RISC OS Sprite bitmap image support via media-libs/librosprite
svgtiny	Use media-libs/libsvgtiny instead of gnome-base/librsvg for SVG support
truetype	Use media-libs/freetype for text in the framebuffer frontend

opera

ffmpeg-chromium	Use Chromium FFmpeg fork (media-video/ffmpeg-chromium) rather than mainline FFmpeg (media-video/ffmpeg)
proprietary-codecs	Enable codecs for patent-encumbered audio and video formats.

opera-beta

ffmpeg-chromium	Use Chromium FFmpeg fork (media-video/ffmpeg-chromium) rather than mainline FFmpeg (media-video/ffmpeg)
proprietary-codecs	Enable codecs for patent-encumbered audio and video formats.

opera-developer

ffmpeg-chromium	Use Chromium FFmpeg fork (media-video/ffmpeg-chromium) rather than mainline FFmpeg (media-video/ffmpeg)
proprietary-codecs	Enable codecs for patent-encumbered audio and video formats.

qutebrowser

adblock	Enable Brave's ABP-style adblocker library for improved adblocking
widevine	Unsupported closed-source DRM capability (required by Netflix VOD)

seamonkey

chatzilla	Build Mozilla's IRC client (default on)
custom-optimization	Build with user-specified compiler optimizations (-Os, -O0, -O1, -O2, -O3) from CFLAGS (unsupported)
gmp-autoupdate	Allow Gecko Media Plugins (binary blobs) to be automatically downloaded and kept up-to-date in user profiles
ipc	Use inter-process communication between tabs and plugins. Allows for greater stability in case of plugin crashes
lto	Enable Link Time Optimization (LTO). Requires Gold linker
system-av1	Use the system-wide media-libs/dav1d and media-libs/libaom library instead of bundled
system-harfbuzz	Use the system-wide media-libs/harfbuzz instead of bundled
system-icu	Use the sytem-wide dev-libs/icu instead of bundled
system-jpeg	Use the system-wide media-libs/libjpeg-turbo instead of bundled
system-libevent	Use the system-wide dev-libs/libevent instead of bundled
system-libvpx	Use the system-wide media-libs/libvpx instead of bundled
system-png	Use the system-wide media-libs/libpng instead of bundled (requires APNG patches)
system-sqlite	Use the system-wide dev-db/sqlite installation with secure-delete enabled
webrtc	Enable WebRTC support. Disabled by default due to privacy concerns.

surf

savedconfig	Without a saved config.h, this package depends on net-misc/curl and x11-terms/st for a default download mechanism
tabbed	Install surf-open.sh script for running surf in x11-misc/tabbed

uget

aria2	Enable support for net-misc/aria2 through xmlrpc. You'll find the plugin in the app's settings.
control-socket	Enable JSON-RPC over unix domain socket
openssl	Use dev-libs/openssl instead of net-libs/gnutls
rss	Enable uGet feed messages

vivaldi

ffmpeg-chromium	Use Chromium FFmpeg fork (media-video/ffmpeg-chromium) rather than mainline FFmpeg (media-video/ffmpeg)
proprietary-codecs	Use system FFmpeg library to support patent-encumbered media codecs
widevine	Unsupported closed-source DRM capability (required by Netflix VOD)

vivaldi-snapshot

ffmpeg-chromium	Use Chromium FFmpeg fork (media-video/ffmpeg-chromium) rather than mainline FFmpeg (media-video/ffmpeg)
proprietary-codecs	Use system FFmpeg library to support patent-encumbered media codecs
widevine	Unsupported closed-source DRM capability (required by Netflix VOD)

w3m

gdk-pixbuf	Enable support for x11-libs/gdk-pixbuf
lynxkeymap	If you prefer Lynx-like key binding

www-misc

litmus

libproxy	Support for automatic proxy configuration management through net-libs/libproxy.
libxml2	Use dev-libs/libxml2 to parse XML
pkcs11	Support for PKCS #11 through PaKChoiS (dev-libs/pakchois).

www-plugins

lightspark

ppapi	Install the PPAPI plugin (for Chromium)
rtmp	Enable Real Time Messaging Protocol using librtmp

passff-host

chrome	Install plugin for chrome (which also includes opera)
chromium	Install plugin for chromium
firefox	Install plugin for firefox
vivaldi	Install plugin for vivaldi

www-servers

apache

static	Link in apache2 modules statically rather then plugins
suexec	Install suexec with apache
suexec-caps	Install suexec with capabilities instead of SUID
suexec-syslog	Log suexec to syslog instead of to a separate file

caddy

events-handlers-exec	Builds a module which lets user exec command on Caddy events https://caddyserver.com/docs/modules/events.handlers.exec https://caddyserver.com/docs/caddyfile/options#event-options
security	Authentication, Authorization, and Accounting. LDAP, OAuth, SAML, MFA, 2FA, JWT etc.. https://caddyserver.com/docs/modules/security https://github.com/greenpau/caddy-security

civetweb

server	Build standalone server

fnord

auth	Enable HTTP authentication support

gatling

diet	Compile against dev-libs/dietlibc

h2o

libh2o	Build and install libh2o
mruby	Enable support for mruby

kore

acme	Add support for ACME
http	Add support for HTTP
json	Add support for JSONRPC
openssl	Use the openssl TLS backend

lighttpd

brotli	Enable output compression via app-arch/brotli (recommended)
gnutls	Build module for TLS via net-libs/gnutls
libdeflate	Enable output compression via app-arch/libdeflate
maxminddb	Add support for geolocation using dev-libs/libmaxminddb
mbedtls	Build module for TLS via net-libs/mbedtls
nettle	Use dev-libs/nettle as crypto library
nss	Build module for TLS via Mozilla's Network Security Services
webdav	Enable webdav properties
zlib	Enable output compression via gzip or deflate algorithms from sys-libs/zlib
zstd	Enable output compression via Zstandard (app-arch/zstd) algorithm

nginx

aio	Enables file AIO support
http	Enable HTTP core support
http-cache	Enable HTTP cache support
http2	Enable HTTP2 module support
http3	Enable HTTP3 module support
ktls	Enable Kernel TLS offload (kTLS)
libatomic	Use libatomic instead of builtin atomic operations
pcre-jit	Enable JIT for pcre
pcre2	Enable support for pcre2
rtmp	NGINX-based Media Streaming Server
ssl	Enable HTTPS module for http. Enable SSL/TLS support for POP3/IMAP/SMTP for mail.

nginx-unit

php8-1	Support for PHP 8.1
php8-2	Support for PHP 8.2

pshs

magic	Enable automatic detection of Content-Type using libmagic (sys-apps/file)
qrcode	Enable generating QRCodes for server URL

sniproxy

dns	Enable DNS resolver via net-libs/udns
largefile	Enable large file support (so we can log more than 2GB)
rfc3339	Use RFC3339 timestamp format in log.

tomcat

extra-webapps	Build also the docs and examples webapp

uwsgi

embedded	Embed plugins instead of building them as real plugins. When disabling this USE flag make sure you specify all used plugins in your uWSGI configuration. Note: Language plugins will always be built as real plugins.
go	Build the gccgo plugin to run Go applications.
json	Support json as a configuration file format.
routing	Enable routing support
yajl	Use dev-libs/yajl instead of dev-libs/jansson for parsing JSON configuration files (if USe=json is set)
yaml	Support yaml as a configuration file format.
zeromq	Enable logging and deployment via ZeroMQ.

xsp

developer	creates .mdb files for either Release and Debug
net35	use .NET 3.5 Framework
net40	use .NET 4.0 Framework
net45	use .NET 4.5 Framework

x11-apps

igt-gpu-tools

X	Enable intel-gpu-overlay xlib/cairo backend
chamelium	Enables support for building Chamelium tests
overlay	Build the intel-gpu-overlay utility
runner	Build the test runner
tests	Build and install tests
xv	Enable intel-gpu-overlay xv backend

xdpyinfo

dmx	Builds support for Distributed Multiheaded X x11-base/xorg-server

xinit

twm	Control dependencies on legacy apps (xterm, twm, ...). Safe to disable if you use a modern desktop environment.

x11-base

xorg-server

elogind	Use elogind to get control over framebuffer when running as regular user
unwind	Enable libunwind usage for backtraces
xcsecurity	Build Security extension
xephyr	Build the Xephyr server
xnest	Build the Xnest server
xorg	Build the Xorg X server (HIGHLY RECOMMENDED)
xvfb	Build the Xvfb server

xwayland

libei	Enable emulated input using dev-libs/libei
unwind	Enable libunwind usage for backtraces
xcsecurity	Build Security extension

x11-drivers

nvidia-drivers

kernel-open	Use the open source variant of the drivers (Turing/Ampere+ GPUs only, aka GTX 1650+ -- recommended with >=560.xx drivers if usable)
persistenced	Install the persistence daemon for keeping devices state when unused (e.g. for headless)
powerd	Install the NVIDIA dynamic boost support daemon (only useful with specific laptops, ignore if unsure)
static-libs	Install the XNVCtrl static library for accessing sensors and other features
tools	Install additional tools such as nvidia-settings

xf86-video-geode

ztv	Enable building the V4L2 ZTV driver

xf86-video-intel

sna	Enable SandyBridge's New Acceleration (useful on all chipsets, not just SandyBridge)
tools	Build the intel-virtual-output tool
uxa	Enable UMA Acceleration Architecture
xvmc	Enables X-Video Motion Compensation support

xf86-video-openchrome

viaregtool	Install registers dumper tool

xf86-video-qxl

xspice	Include Xspice, a standard X server that is also a Spice server

x11-libs

agg

gpc	Enable gpc polygon clipper library

cairo

glib	Compile with GLib Object System support

fltk

games	Builds and installs some extra games

fox

tools	Install adie, calculator, shutterbug, and pathfinder apps.

gtk+

broadway	Enable the GDK Broadway backend
cloudproviders	Enable GtkPlacesSidebar to access cloud services
colord	Use x11-misc/colord for color management in printing
sysprof	Enable profiling data capture support using dev-util/sysprof-capture

gtkdatabox

glade	Build with libglade and glade-3 supports, which includes a glade's module for GtkDataBox widget

gtkmathview

mathml	Install additional fonts for proper mathml support.
t1lib	Enable media-libs/t1lib support

gtksourceview

glade	Install a glade catalog file

libQGLViewer

designer	Installs dev-qt/designer plugin.

libSM

uuid	Use UUID for session identification instead of IP address and system time.

libXaw

deprecated	Install deprecated Xaw6 library.

libXfont2

bzip2	Support bzip2 compressed PCF fonts.
truetype	Use media-libs/freetype for font rasterization.

libdlo

test-program	Build the program for testing Displaylink devices.

libdrm

tools	Install optional tests and tools

libfm

automount	Use gnome-base/gvfs for automounting
udisks	Use libfm's udisks-based volume monitor implementation instead of using the one from gvfs
vala	Support custom actions in menus

libwnck

tools	Install wnckprop-3 and wnck-urgency-monitor-3 command-line tools

libxcb

xkb	Enable the XCB keyboard extension

libxkbcommon

tools	Build the xkbcli tools

pango

X	Build and install the legacy pangoxft library
sysprof	Enable profiling data capture support using dev-util/sysprof-capture

pixman

loongson2f	Enable Loongson2f MMI optimizations.

qscintilla

designer	Build plugin for Qt Designer

qwt

designer	Installs dev-qt/designer plugin.
polar	Install the QwtPolar headers

tslib

evdev	Build experimental input module
uinput	Provide alternative ts_uinput evdev device

vte

icu	Enable legacy charset support using dev-libs/icu
systemd	Support moving terminal child processes to their own systemd user scopes to avoid terminal getting killed due to child causing OOM

wxGTK

gstreamer	Enable the wxMediaCtrl class for playing audio and video through gstreamer.
sdl	Use Simple Directmedia Layer (media-libs/libsdl) for audio.

xapp

mate	Install integrations for mate-base/mate
xfce	Install integrations for xfce-base/xfce4-meta

x11-misc

alock

doc	Build and install manpage with app-text/asciidoc.

appmenu-gtk-module

gtk2	Build module for GTK+2

autorandr

launcher	Install the launcher, i.e., an alternative to the udev/systemd hooks

bumblebee

bbswitch	Add dependency on sys-power/bbswitch for PM feature

clipmenu

dmenu	Use dmenu as default launcher
fzf	Use fzf as default launcher
rofi	Use rofi as default launcher

colord

argyllcms	Enable ArgyllCMS sensor
extra-print-profiles	Generate extra print profiles. Warning: significant build time and memory requirements.

copyq

notification	Build with native notification support (requires kde-frameworks/knotifications:5)

fbpager

xrender	Enable transparency support via x11-libs/libXrender

gammastep

geoclue	Control dependency on app-misc/geoclue

gmrun

xdg	Enable xdg spec for configuration and history files location

gpaste

gnome	Enable proper gnome support and enable gnome shell extension.

grsync

gtk3	Link against x11-libs/gtk+:3 instead of x11-libs/gtk+:2

i3blocks

contrib	Install contrib modules

i3status

filecaps	Linux capabilities library is required for i3status to be able to read net bandwidth

j4-dmenu-desktop

dmenu	Use x11-misc/dmenu as default. Disable to use a different implementation.

ktsuss

sudo	Use the sudo backend instead the su one

libinput-gestures

experimental	avoid producing zombie processes

light-locker

dpms	Turn on the display on screensaver deactivation.
screensaver	Lock the screen on screensaver activation.

lightdm

gtk	Pull in the gtk+ greeter
non-root	Use non-root user by default

mugshot

gnome	Add support for gnome-base/gnome-control-center
libreoffice	Add support for app-office/libreoffice and app-office/libreoffice-bin
webcam	Add support for setting a profile photo in media-video/cheese

openbox-menu

icons	Enable support for icons in menus
svg	Support SVG icons

picom

config-file	Enable config file support
doc	Build documentation and man pages (requires app-text/asciidoc)
drm	Enable support for using drm for vsync
opengl	Enable features that require opengl (opengl backend, and opengl vsync methods)

polybar

i3wm	Add support for i3 window manager
ipc	Add support for Inter-Process Messaging
mpd	Add support for Music Player Daemon
network	Enable network support

primus

libglvnd	Use media-libs/libglvnd for dispatch

py3status

minimal	Don't depend on x11-misc/i3status if you don't plan to use any of its built-in modules.
udev	Install extra requirement dev-python/pyudev to enable udev events monitoring on modules.

qtfm

dbus	Install the qtfm-tray removable device manager
shared	Install the libQtFM shared library and headers

read-edid

vbe-mode	Build get-edid with support for legacy, VBE-based interface. Requires dev-libs/libx86.

redshift

geoclue	Control dependency on app-misc/geoclue

rofi

drun	Enable desktop file run dialog
windowmode	Enable normal window mode

rss-glx

quesoglc	Enable support for OpenGL Character Renderer

sent

savedconfig	Without a saved config.h, this package depends on media-gfx/farbfeld for image conversions

spacefm

video-thumbnails	Support video thumbnails with media-video/ffmpegthumbnailer

stalonetray

graceful-exit	use non-portable hack to exit gracefully on signal

tint2

battery	Enable battery status plugin
sanitize	Enable ASAN
tint2conf	Build/Install tint2conf as well

urxvt-perls

deprecated	Install scripts which have been marked as deprecated by upstream

wbar

gtk	Enables the gtk-based wbar-config GUI

x11vnc

xdamage	Enable support for the Xdamage library
xfixes	Enable support for the Xfixes library
xrandr	Enable support for the X xrandr extension

xkbd

evdev	Enable dev-libs/libevdev support for xtg
xi	Enable XInput2 support through x11-libs/libXi
xrandr	Enable XRandR support through x11-libs/libXrandr

xkbset

tk	Install the dev-perl/Tk based xkbset-gui utility

xlockmore

vtlock	Enables support for virtual terminal locking
xlockrc	Enables xlockrc for people without PAM

xmobar

alsa	Use alsa-mixer to get the volume from soundcards.
datezone	Enables localized date support.
dbus	Publish a service on the session bus for controlling xmobar.
mpd	MPD support. Needs libmpd installed.
mpris	MPRIS v1, v2 support.
rtsopts	Use -with-rtsopts=-V0 to reduce wakeups.
timezone	Enables localized date support.
uvmeter	UVMeter only useful to australians.
weather	Enable weather plugin.
wifi	Wireless info support via nl80211. Required for the Wireless plugin on systems running Linux, the kernel.
xft	Use Xft to render text. UTF-8 support included.
xpm	Enable usage of xpm for icons.
xrender	Use XRender for alpha background pseudo-transparency.

xscreensaver

fonts	Install the fonts shipped with XScreenSaver that have clear licensing
gdm	Use gdmflexiserver from gnome-base/gdm instead of x11-misc/lightdm
gles	Emulate OpenGL 1.3 in terms of OpenGL ES 1.x
glx	Use GLX to interface OpenGL and X11 instead of EGL
locking	Compile in support for locking the display
logind-idle-hint	Send the session idle hint to logind once the screen saver blanks
new-login	Enable user switching support using gdmflexiserver (x11-misc/lightdm)

xsr

cursor	Capture mouse cursor using x11-misc/xdotool, and place them on the screenshots using media-gfx/imagemagick

yabar

playerctl	Uses media-sound/playerctl to retrieve the name of the currently played song

x11-plugins

bfm

gkrellm	Enable building of app-admin/gkrellmmodule

e16-epplets

cdaudio	Enable CD Audio support using media-libs/libcdaudio
libgtop	Use gnome-base/libgtop to obtain system load information

pidgin-mbpurple

twitgin	Enable graphical plugin for Gtk+ interface of Pidgin.

pidgin-sipe

ocs2005-message-hack	Disable message timeout for OCS2005 clients which causes "false" not delivered error messages
openssl	Enable crypto support via dev-libs/openssl
telepathy	Support use as a telepathy backend
voice	Enable experimental voice/video support

vicious

contrib	Install extra widgets, some for less common hardware, some contributed by Vicious users.

wmbattery

apm	Add APM (Advanced Power Management) support

wmfire

session	Enable session management

wmudmount

gcr	Enable support for secure memory with app-crypt/gcr

x11-terms

aterm

background	Enable background image support via media-libs/libafterimage
xgetdefault	Enable resources via X instead of aterm small version

gnome-terminal

gnome-shell	Integrate with gnome-base/gnome-shell search
nautilus	Build gnome-base/nautilus extension

mlterm

brltty	Enable support for app-accessibility/brltty
fcitx	Enable support for app-i18n/fcitx
harfbuzz	Enable support for OpenType Layout (media-libs/harfbuzz)
ibus	Enable support for app-i18n/ibus
libssh2	Enable support for net-libs/libssh2
regis	Enable support for ReGIS
scim	Enable support for app-i18n/scim
skk	Enable support for SKK (virtual/skkserv or app-i18n/skk-jisyo)
uim	Enable support for app-i18n/uim
utempter	Enable support for sys-libs/libutempter
wayland	Enable support for Wayland

rxvt-unicode

24-bit-color	Enable 24-bit color support. Note that this feature is unofficial, may cause visual glitches due to the fact there is no termcap/terminfo definition for rxvt-unicode-24bit yet so it is necessary to use the one for 256 colours, visibly increases memory usage, and might slow urxvt down dramatically when more than six fonts are in use in a terminal instance.
256-color	Enable 256 color support
blink	Enable blinking text
fading-colors	Enable colors fading when off focus
font-styles	Enable support for bold and italic fonts
gdk-pixbuf	Enable transparency support using x11-libs/gdk-pixbuf
iso14755	Enable ISO-14755 support
mousewheel	Enable scrolling via mouse wheel or buttons 4 and 5
perl	Enable perl script support. You can still disable this at runtime with -pe ""
unicode3	Use 21 instead of 16 bits to represent unicode characters
wide-glyphs	Enable support for wide glyphs, required for certain symbol/icon fonts to display correctly. Note that this feature is *unofficial* and has been observed to cause stability issues for some users.

terminology

extras	Install additional testing tools

xfce4-terminal

utempter	Include utmp management support via sys-libs/libutempter

xterm

openpty	Use openpty() in preference to posix_openpt()
sixel	Enable sixel graphics support
toolbar	Enable the xterm toolbar to be built

x11-themes

QGnomePlatform

minimal	Skip kde-frameworks/qqc2-desktop-style dependency (Warning: some apps could be wrongly rendered)

arc-theme

cinnamon	Install theme for gnome-extra/cinnamon
gnome-shell	Install theme for gnome-base/gnome-shell
gtk2	Install GTK+2 theme
gtk3	Install GTK+3 theme
gtk4	Install GTK+4 theme
mate	Install Metacity theme for mate-base/mate
pre-rendered	Avoid media-gfx/inkscape and media-gfx/optipng dependencies by using pre-rendered PNGs
transparency	Enable transparency
xfce	Install theme for xfce-base/xfwm4

comix-xcursors

lefthanded	Install lefthanded version of theme in addition to default one.
opaque	Install non-transparent version of theme in addition to default one.

fluent-icon-theme

hardlink	Hardlink duplicate icons to greatly reduce installation size
round	Install the round version of symbolic icons

gentoo-artwork

grub	Install extra sys-boot/grub themes
icons	Install icons
lilo	Install extra sys-boot/lilo themes
pixmaps	Install pixmaps

gtk-engines-murrine

animation-rtl	Progressbar animation from right to left
themes	Pull in themes via x11-themes/murrine-themes

kfaenza

additional	Install additional KFaenza icons. See third homepage for details

tela-icon-theme

hardlink	Hardlink duplicate icons to greatly reduce installation size

vertex-theme

cinnamon	Install theme for gnome-extra/cinnamon
gnome-shell	Install theme for gnome-base/gnome-shell
mate	Install Metacity theme for mate-base/mate
xfce	Install theme for xfce-base/xfwm4

zuki-themes

gnome-shell	Install theme for gnome-base/gnome-shell
gtk2	Install GTK+2 theme
xfce	Install theme for xfce-base/xfwm4

x11-wm

ctwm

jpeg	Enable jpeg image support with virtual/jpeg
test	Enable upstream test suite, build required binary
xpm	Enable xpm icon support with x11-libs/libXpm

e16

debug	Build libtrip debugging library
dialogs	Enable support for configuration dialogs
libhack	Build libhack window mode helper library
modules	Enable support for loadable modules
no-container	Do not use container window (experimental)
pango	Enable pango font rendering using x11-libs/pango
player	Enable audio using aplay from media-sound/alsa-utils
poll	Use poll() event handler API (recommended)
select	Use select() event handler API
themes	Install the official E16 themes using x11-themes/e16-themes
xi2	Enable the experimental multipointer input XInput2. This incldues the MultiPointer X feature
xpresent	Enable support for the X Present extension via x11-libs/libXpresent (experimental)
xrandr	Enable support for the X RandR extension via x11-libs/libXrandr
xrender	Enable transparency support using the X Render extension via x11-libs/libXrender
xsm	Enable X Session Management support using x11-libs/libSM
xsync	Enable X Sync support
zoom	Support resolution change of current window (zoom) usingx11-libs/libXxf86vm (xvidtune)

echinus

xrandr	Enable support for multihead configuration

enlightenment

xwayland	Enable XWayland application support

fluxbox

slit	Enables the Fluxbox slit (or dock)
systray	Enables the system tray in the Fluxbox toolbar
toolbar	Enables the Fluxbox toolbar

fvwm

lock	Enable screen locking
netpbm	Enable NetPBM support (used by FvwmScript-ScreenDump)
stroke	Mouse Gesture support

fvwm3

go	Enable building dev-lang/go code (FvwmPrompt)
lock	Enable screen locking
netpbm	Enable NetPBM support (used by FvwmScript-ScreenDump)
stroke	Mouse Gesture support

i3

doc	Build and install the HTML documentation and regenerate the man pages

icewm

gdk-pixbuf	Enable gdk-pixbuf rendering

jwm

pango	Bidirectional text layout support with pango using xft backend.

lumina

desktop-utils	Build and install lumina's desktop-utils

metacity

libcanberra	Enable sound event support using media-libs/libcanberra
vulkan	Enable Vulkan based compositor support via META_COMPOSITOR=vulkan environment variable

muffin

sysprof	Enable profiling data capture support using dev-util/sysprof-capture

musca

apis	Optionally install the experimental `apis' window manager
xlisten	Optionally install the xlisten utility

mutter

elogind	Rely on sys-auth/elogind as logind provider for Wayland sessions
sysprof	Enable profiling data capture support using dev-util/sysprof-capture

notion

xrandr	Add support for xrandr

openbox

session	Enables support for session managers
xdg	Install the python xdg files for xdg autostart

pekwm

contrib	Install optional extras in the documentation directory
pango	Pango font support
themes	Install additional themes

ratpoison

history	Use sys-libs/readline for history handling
sloppy	Install sloppy, a focus-follows-mouse implementation for ratpoison
xrandr	Enable support for XRandR

stumpwm

doc	Include documentation

windowmaker

modelock	Enable XKB language status lock support. README says: "If you don't know what it is you probably don't need it."
xrandr	Enable XRandR window extension support

wmfs

imlib2	Enable image support through media-libs/imlib2

xmonad

no-autorepeat-keys	Allow ignoring of keyboard autorepeat.

xmonad-contrib

xft	Use Xft to render text

xpra

client	Build client-side code
clipboard	Enable clipboard support
csc	Enable csc softscaler support
gtk3	Enable the GTK3 client
html	Install the HTML5 client
ibus	Use ibus input method via app-i18n/ibus
mdns	Enable Multicast DNS via dev-libs/mdns
oauth	Enable OAuth2 authentication in the server
openh264	Enable H.264 support using media-libs/openh264
pinentry	Use app-crypt/pinentry for password entry
qrcode	Enable generating QRCodes for server URL via media-gfx/qrencode
server	Build server-side code
trayicon	Enable system tray icon
vpx	Enable vpx image format support
webcam	Enable webcam support via opencv
xdg	Enable support for XDG-based menus

xfce-base

libxfce4ui

glade	Build support for Glade 3's GtkBuilder implementation
system-info	Enable system information in xfce4-about.

thunar

trash-panel-plugin	Build the trash status indicator plugin for the XFCE panel

tumbler

epub	Enable support for .epub thumbnailer using app-text/libgepub
odf	Enable support for .odf thumbnailers by using gnome-extra/libgsf

xfce4-meta

archive	Install app-arch/xarchiver.
editor	Install the app-editors/mousepad text editor.
image	Install the media-gfx/ristretto image viewer.
media	Install the media-video/parole media player.
mpd	Install the media-sound/xfmpc MPD client.
remote-fs	Install the x11-misc/gigolo frontend to manage remote filesystem connections.
search	Install the dev-util/catfish search tool frontend.

xfce4-panel

dbusmenu	Enable dev-libs/libdbusmenu integration (in status notifier plugin)

xfce4-power-manager

panel-plugin	Build the power management plugin for the XFCE panel

xfce4-settings

libcanberra	Enable sound event support using media-libs/libcanberra
xklavier	Enable keyboard layout selection support using x11-libs/libxklavier

xfdesktop

thunar	Build support for desktop icons (for example, launchers and folders)

xfwm4

xpresent	Enable the XPresent extension for sync to vblank

xfce-extra

xfce4-clipman-plugin

qrcode	Enable support for media-gfx/qrencode

xfce4-mixer

keybinder	Enable support for global hotkeys using dev-libs/keybinder.
sndio	Enable media-sound/sndio backend.

xfce4-pulseaudio-plugin

keybinder	Enable support for global hotkeys using dev-libs/keybinder.
libcanberra	Enable sound event support using media-libs/libcanberra
libxfce4windowing	Enable experimental support for raising media player windows using xfce-base/libxfce4windowing.
wnck	Enable experimental support for raising media player windows using x11-libs/libwnck.

xfce4-screensaver

locking	Enable screen locking support

xfce4-whiskermenu-plugin

accountsservice	Enable support for AccountsService.