Comment 3 for bug 1546636

Some notes on this:

For 3.18, the system.xml list mostly corresponded to the applications in GNOME core, with the exception of gedit, which was not in core at the time.

For 3.20, I added a bunch of applications into core (including gedit); now the system.xml list is outdated. We decided not to update system.xml in order to allow users to remove these applications, with the result that the definition of what's in system.xml is historical and arbitrary. This is not good.

Now, for 3.22, we've switched to using <compulsory_for_desktop> tags in appdata and removed system.xml. Not sure if that's actually a good change, as it makes it much harder to edit the list, but it does avoid the problem of having the list hardcoded in gnome-software. Currently we have the same set of arbitrary applications marked with <compulsory_for_desktop> and we need to figure out something better. Nothing has been decided; we're leaning towards allowing removal of pretty much anything short of gnome-control-center as it's quite annoying to have unremovable applications without good reason, but not 100% happy with this as I'm not keen to lose the concept of system applications.

It would be great for Ubuntu to join in the upstream discussion: https://bugzilla.gnome.org/show_bug.cgi?id=760697