XEmacs is a self-documenting, customizable, extensible, real-time
display editor. XEmacs is self-documenting because at any time you can
type in control-h to find out what your options are or to find out
what a command does. XEmacs is customizable because you can change the
definitions of XEmacs commands to anything you want. XEmacs is
extensible because you can write entirely new commands--programs in
the Lisp language to be run by Emacs' own Lisp interpreter. XEmacs
includes a real-time display, which means that the text being edited
is visible on the screen and is updated very frequently (usually after
every character or pair of characters) as you type.

To use XEmacs, you'll need to install the XEmacs binary. The xemacs package
includes the standard XEmacs binary that most people will use. The XEmacs
binary is dynamically linked, with both X11 and TTY (ncurses) support, but
without mule (MUlti-Lingual Emacs, the Asian character set) support.