The Free Software Foundation holds copyright of much of the XEmacs code because of prior copyright assignment during merge attempts and cross-development. Whether a piece of new XEmacs code enters GNU Emacs often depends on the willingness of that individual contributor to assign the code to the FSF. New features in either editor usually show up in the other sooner or later. Furthermore, many developers contribute to both projects.
The Free Software Foundation holds copyright of much of the XEmacs code because of prior copyright assignment during merge attempts and cross-development. Whether a piece of new XEmacs code enters GNU Emacs often depends on the willingness of that individual contributor to assign the code to the FSF. New features in either editor usually show up in the other sooner or later. Furthermore, many developers contribute to both projects.