Re-reporting this as the original task went to hell in a handbasket with tantrums (T3896)
Right now adding new menu extensions to GNOME Shell doesn't work correctly due to a borked "Activities" button, thus the "Applications Menu" extension doesn't work.
Most important detail: Applications Menu doesn't actually work.
Probable cause: We ship all of the default extensions in the gnome-shell-extensions package, and likely the classic extensions are causing a conflict.
Apologies that you had to suffer that @tristan957 - pretty sure you know I wasn't actually lowering the priority, but doing it only in the UI to make a point. :p
Yerp, impossible to figure out in a VM :P Gonna install locally and discombobulate it
Alright @tristan957 this is gonna sound super stupid ... :P
Can you install libgnome-menus, or this update (which only adds that dependency) and verify if the issue is gone for you please?
GNOME Shell/GJS/etc did not spit out any errors about this hence us not finding it sooner. But now I've had a couple of minutes
to actually poke it (literally a couple of minutes) I confirm the fix in my VM and an installation.
This worked. One thing to add. When I first went to enable the extension I received an error. It did work after restart though. Should be good to go!