You can debug mutter (used in gnome-shell) by setting its environment
variables. These need to be set prior to run gnome-shell, so if you
want to log into GNOME from GDM, you need to create a wrapper script
called from a desktop file in /usr/share/wayland-sessions.
FIXME: Putting the wrapper script and desktop file here would be helpful."
Any chance anyone with time and interest to fix the fixme here?
You might want to ping jadahl or ofourdan (#fedora-desktop or #gtk+ on gimpnet), I believe
I received that quoted info from one of them. If you receive more info on debugging
mutter, please put it into the wiki, thanks.