[AppStream] Appstream ID and Flatpak

[Aleix Pol]

Hey,
In KDE's Discover (and I'm pretty sure Gnome Software too) we rely on
the appstream id to de-duplicate applications: if packagekit, flatpak
or snap offer me an application, we will choose the one from the
backend we prefer, rather than showing the 3 of them.

This premise is broken on many flatpak applications specifically as
it's more strict than distributions and doesn't allow applications to
ship without the rdns id. Some applications then will workaround this
requirement by renaming the appstream in the packaging [2] or by just
adding the appstream information with a different name and renaming
the desktop file [3].

I'm not sure if this is a known issue or what's the plan here, I'd
suggest as a first approach to deprecate "rename-appdata-file" from
flatpak-builder manifests and push packagers to actually get upstream
to do the right thing. At least this way we will have the metadata
converge at some point.

Aleix

[1] https://bugs.kde.org/show_bug.cgi?id=387790
[2] https://github.com/flathub/io.github.Hexchat/blob/master/io.github.Hexchat.json#L8
[3] https://github.com/flathub/org.blender.Blender