Public bug reported: I don't know for a fact that Ubuntu isn't running mutter using GTK2, but I suspect that it's probably a documentation bug, since Ubuntu tries to use later versions of GTK in their projects. Also, GTK2 apparently hasn't been the default version of GTK used in mutter since 2010, going by this commit in their repository:
https://gitlab.gnome.org/GNOME/mutter/-/commit/069092eb9dae48a0aaa208728ad58d997d444221 ** Affects: mutter (Ubuntu) Importance: Undecided Status: New -- You received this bug notification because you are a member of Ubuntu Desktop Bugs, which is subscribed to mutter in Ubuntu. https://bugs.launchpad.net/bugs/2016411 Title: Man page says that project is a GTK2 project. To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/mutter/+bug/2016411/+subscriptions -- desktop-bugs mailing list desktop-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/desktop-bugs