For ushyphex.tex, which is also added to the end of hyph-en-us.hyp.txt:
% Copyright 2008 TeX Users Group.
% You may freely use, modify and/or distribute this file.

For other files:
% Copyright (C) 1990, 2004, 2005 Gerard D.C. Kuiken.
% Copying and distribution of this file, with or without modification,
% are permitted in any medium without royalty provided the copyright
% notice and this notice are preserved.