> > I don't see the relation between sandboxable and unremovable.
> >
>
> On an image-based OS, wouldn't it be the case that anything that's
> not a flatpak would be part of the image, and therefore unremovable?
> I've been looking at this issue recently from a slightly different
> perspective and wondered whether "part of the base OS" might be a
> simpler and more natural replacement for <mandatory_for_desktop>.
Seems to me that the whole problem is that gnome-software keeps the
"package" uninstallable even if the same application is installed via
Flatpak.
Fix that, and you don't need to make any changes to the appdata files.