GPL file header

src/license-gpl-file.py

@@ -0,0 +1,17 @@
+# SPDX-License-Identifier: (GPL-3.0-or-later)
+"""
+This file is part of Foobar.
+
+Foobar 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 3 of the License, or (at your option)
+any later version.
+
+Foobar 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, see <https://www.gnu.org/licenses/>.
+"""