High Quality Content by WIKIPEDIA articles! SXEmacs is a fork of the XEmacs text editor. It runs on many Unix-like operating systems, and is notable for features such as FFI support, enhanced number types (similar to bignums in XEmacs 21.5), raw string regexps, and an implementation of Pugh`s skip lists. Any user can download SXEmacs as free software available under Version 3 of the GNU General Public License.