alsa - Add support for media-libs/alsa-lib (Advanced Linux Sound Architecture)
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
deprecated - Enable support for deprecated features
fontconfig - Support for configuring and customizing font access via media-libs/fontconfig
gui - Enable support for a graphical user interface
pulseaudio - Add sound server support via media-libs/libpulse (may be PulseAudio or PipeWire)
raycast - Enable the raycast Editor module using media-libs/embree
test - Enable dependencies and/or preparations necessary to run tests (usually controlled by FEATURES=test but can be toggled independently)
theora - Add support for the Theora Video Compression Codec
tools - Enable the Godot Editor for game development
udev - Enable virtual/udev integration (device discovery, power and storage device support, etc)