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.