Programmer errors with GSettings cause segfaults
I'm not sure if this has been filed before (couldn't find an open or closed issue), but it's certainly well known among GJS and extension authors. Virtually any programmer error with regard to GSettings causes a segfault. Here's a two-line reproducer:
const Gio = imports.gi.Gio; let settings = new Gio.Settings();
While granted these are programmer errors, it's not only extremely unforgiving for new developers, with an application that is automatically started/restarted a simple typo can cause it to start, segfault and repeat indefinitely.
In the case of Gnome Shell, this can end your session and prevent it from being started. If the culprit is a Shell extension and the error is reached as a result of user interaction, it's not unreasonable to think such an error could slip past the extension review process. For an end-user unfamiliar with how to diagnose or fix this from a tty, it can leave them in position where they can't even get help.