XEmacs

• XEmacs   - Official site. Open source text editor for GUI environments. Includes downloads, documentation, getting involved in development and customization. [Linux, Unix, Windows]

• 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.
• XEmacs Editor FAQ - Frequently asked questions covering internationalization, troubleshooting, customization, user guidance and release notes.