Isn't that effectively the same as or-later? I can always fork your project, change the MAINTAINERS file, and relicense without your consent.

Indeed, it would need to be more specific, and say this list of people in this repo.

Uh yes of course, I thought of that and thought "isn't that neat" but of course it goes against exactly what the author wants. I don't find this fear very natural I suppose! A different trusted third party could be nominated, I guess (KDE project nominate KDE e.V. for instance).