Emacs denominates a class of powerful, extensible, self-documenting text editors. The original implementation still updated today is GNU Emacs, a derivative is XEmacs, which was forked from GNU Emacs in the early 1990s. The latter is not the X version of Emacs but a complete separate program.
Apart from the two big contenders, many lightweight implementations exist, many of which are available in Gentoo:
|Editor name||Gentoo package|
|GNU Emacs||app-editors/emacs (releases) or app-editors/emacs-vcs (live version)|
layman -a emacs
Many more emacs-related packages should now be available for installation.