abbrev        abbreviation handling, typing shortcuts, macros
bib           code related to the ‘bib’ bibliography processor
c             C, C++, and Objective-C language support
calendar      calendar and time management support
comm          communications, networking, remote access to files
data          support for editing files of data
docs          support for Emacs documentation
dumped        files preloaded into Emacs
emulations    emulations of other editors
extensions    Emacs Lisp language extensions
faces         support for multiple fonts
frames        support for Emacs frames and window systems
games         games, jokes and amusements
hardware      support for interfacing with exotic hardware
help          support for on-line help systems
hypermedia    support for links between text or other media types
i18n          internationalization and alternate character-set support
internal      code for Emacs internals, build process, defaults
languages     specialized modes for editing programming languages
lisp          Lisp support, including Emacs Lisp
local         code local to your site
maint         maintenance aids for the Emacs development group
mail          modes for electronic-mail handling
matching      various sorts of searching and matching
mouse         mouse support
mule          multi-language extensions
news          support for netnews reading and posting
oop           support for object-oriented programming
outlines      support for hierarchical outlining
processes     process, subshell, compilation, and job control support
terminals     support for terminal types
tex           code related to the TeX formatter
tools         programming tools
unix          front-ends/assistants for, or emulators of, UNIX features
vms           support code for vms
wp            word processing