SPDX-License-Identifier: GPL-3.0-or-later
As is conventional, this should be read as a licence grant.
+The Debian packaging files in the debian/ subdirectory are under a
+more permissive licence - the MIT licence, debian/MIT-LICENCE, as
+indicated in those files by:
+ SPDX-License-Identifier: MIT
+(This is useful only if (parts of) these files are copied elsewhere,
+since as provided by the GPL3, when the package is distributed as a
+work as a whole, these files are covered by the GPL3.)
+
Contributions are accepted based on the git commit Signed-off-by
convention, by which the contributors' certify their contributions
according to the Developer Certificate of Origin version 1.1 - see