This is the current version of XEmacs, formerly known as Lucid-Emacs.
It is related to other versions of Emacs, in particular GNU Emacs. Its
emphasis is on modern graphical user interface support and an open
software development model, similar to Linux.

Lisp macros are not necessarily interchangeable between GNU-Emacs and
XEmacs. This is mainly important for translated .elc files and the key
macros.