libmutter-test-11 43.0-1ubuntu5 (amd64 binary) in ubuntu lunar

 Mutter is a Wayland display server and X11 window manager and
 compositor library. It contains functionality related to, among other
 things, window management, window compositing, focus tracking, workspace
 management, keybindings and monitor configuration.
 .
 This package contains a private library used by the automated tests for
 mutter and gnome-shell. It should not be used by non-GNOME packages.