Install xemacs21-support by entering the following commands in the terminal:
sudo apt update sudo apt install xemacs21-support
Description:
highly customizable text editor -- architecture independent support 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. . Support and architecture independent files for XEmacs 21.4.22. This includes the files found in etc and all required elisp library files (mostly compiled (.elc files), but a few uncompiled (.el files)).
Homepage: http://www.xemacs.org/
Version: 21.4.24-5ubuntu1
Section: universe/editors