Looking at the file "nt/Emacs.ad.h" in the archives it seems like it
was first introduced in 20.1 beta2 where the first MS Windows NT
support was added attributed to David Hobley.
Some of the files added at the same time in the nt directory have
GPLv2 or later notices. The others are missing copyright and
license. So I think that the files missing copyright and license, such
as Emacs.ad.h, added at the same time, could be given GPLv2 or later
license and be copyrighted to David Hobley. Right?
Is there anything known about David Hobleys position on the GPLv3
XEmacs-Beta mailing list