If you stumble on one of my projects, you may have seen this licence:
Licence: GPL-2.0-only OR GPL-3.0-or-later with proxy being me
What does that mean? Why did I choose such a long and weird licence?
The reason is that I want:
- to be covered by a strong copyleft licence
- while being compatible with past/future GPL licences (and not block my project from being used with one that uses a different version of the GPL)
- and not give power to the FSF to issue a new licence in the future that I would not agree with.
The solution to this last point is the proxy clause. Quoting GPL 3.0:
If the Program specifies that a proxy can decide which future versions of the GNU General Public License can be used, that proxy’s public statement of acceptance of a version permanently authorizes you to choose that version for the Program.
Unfortunately, this clause is not present in GPL 2, so I explicitly allow it by allowing use of my work under either GPL-2.0-only or GPL-3.0-or-later, given that I accept any “later” licence.
Put this together and you get the following licence expression: ‘GPL-2.0-only OR GPL-3.0-or-later’ (with proxy being me).
Feel free to copy this technique to licence your projects that would otherwise be in GPL-*-only, to allow broader usage of them !