From #openttdcoop wiki
All my work is licensed under GPL (v2 upwards) which includes the following terms:
- You are allowed to use the unmodified NewGRFs for your needs as you like. (commercial and whatever...)
- You are allowed to use the source and modify it as long as your work will go back to the community. With following points.
- free and opensource
- credits also for co-authors
Copyright (C) 2009 Marcel "Ammler" Gmür (email@example.com)
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.
This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110, USA