XEmacs

The Emacs Schism
How XEmacs (Lucid Emacs as was) came about, by Jamie Zawinski: '[t]his incident has become famous as one of the most significant "forks" in a free software code base'. Edited Highlights of mail-lists as events unfolded.
http://www.jwz.org/doc/lemacs.html

XEmacs Editor FAQ
Frequently asked questions covering internationalization, troubleshooting, customization, user guidance and release notes.
http://www.xemacs.org/faq/xemacs-faq.html