Install xemacs21-supportel by entering the following commands in the terminal:
sudo apt update sudo apt install xemacs21-supportel
Description:
highly customizable text editor -- non-required library files
XEmacs is a full fledged programming language with a mail reader, news reader, info browser, web browser, calendar, specialized editor for more programming languages and other formats than most people encounter in a lifetime, and much more. . This package contains all the non-necessary library files for XEmacs. The xemacs21-support package contains the compiled versions of these files. . The major reason to install this package is if you want to learn elisp or modify the libraries for your specific installation.
Homepage: http://www.xemacs.org/
Version: 21.4.24-5ubuntu1
Section: universe/editors