Sandra Wambold <wambold(a)xemacs.org> writes:
[...]
So, XEmacs code *can* be used by anyone, but Stallman chooses not to
use the code.
XEmacs code can *probably* be used by anyone, but there's always the
possibility that someone (or some entity) will come along with
evidence that some bit of it is really owned by them, and isn't really
covered by the GNU GPL. So to try to avoid problems down the line,
rms chooses not to use random XEmacs code.