General Discussion • Re: Do 'silent' crashes leave a report somewhere?

The GTK message about appmenu-gtk-module appears to be a distro/GTK global-menu module warning and is probably unrelated to Pale Moon crashes. If you don't want that warning in the future, the usual fix is installing your distro’s appmenu-gtk-module package if the desktop expects it.

The shutdown ReferenceError is more suspicious. It appears to come from an extension, possibly theme/persona/UI-related. It may be relevant to shutdown crashes or shutdown hangs, but I would not assume it explains unrelated browsing crashes unless those crashes correlate with exit or theme/extension activity.