EL is the extension of files that store program code written in Emacs Lisp. Code written in this language is a variant of the LISP programming language, which has a distinctive syntax. The Emacs Lisp dialect is used in the Emacs and XEmacs code editors. These programs, in addition to the code editor, contain the Emacs Lisp language interpreter. The use of a code editor allows for convenient syntax creation and control. Besides, Emacs can integrate with version control systems.

GNU Emacs is a tool developed by the Free Software Foundation that can work in both graphical and text modes.