Bug#1092099: AppStream data not generated

[asciiwolf at seznam.cz]

Package: darktable
Version: 4.8.1-2

Darktable is missing in GNOME Software and KDE Discover on latest Debian Testing/Sid. It looks like that even though the "darktable" package contains correct AppStream metainfo file, it is not parsed and processed for some reason:

https://appstream.debian.org/sid/main/issues/darktable.html

I have checked and validated the metainfo file and desktop/icon files. Everything looks correct.