Comment 4 for bug 973714

Widelands is not strictly GPLv2 according to our source file headers:
"This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version."
So I think it is no big problem to add GPLv3 content. The whole program/package would be GPLv3 in this case, but the source code could remain GPLv2. But the discussion is slightly off topic here.