The plasma-discover-flatpak-backend package isn't very useful without any repos configured. Right now, Flathub is the only really useful one, so I think it makes sense to add it when the package is installed, to save the user (who is probably non-technical if they want to use the Flatpak backend) from having to figure out that they have to add a Flatpak repo, what one would be, how to do it, etc. I recommended doing this automatically for all distros in https://bugs.kde.org/show_bug.cgi?id=387718, but Discover's author and maintainer advised that this is a distro packager's decision. So here I am, asking Fedora's plasma-discover packagers to automatically add the Flathub repo (https://flathub.org/repo/flathub.flatpakrepo) when plasma-discover-flatpak-backend is installed. :)
This bug appears to have been reported against 'rawhide' during the Fedora 28 development cycle. Changing version to '28'.
One question is how best to implement that (it is a shame upstream poo poo'd doing it by default).
Probably the simplest approach would be to add a shell script command in the packaging that gets run as the very last step of installing the Flatpak backend package is installed: flatpak remote-add --if-not-exists flathub https://flathub.org/repo/flathub.flatpakrepo
FWIW Neon does this by shipping a systemd unit that runs a small script: https://invent.kde.org/neon/neon/settings/-/blob/Neon/unstable/debian/neon-settings-2.neon-flathub.service https://invent.kde.org/neon/neon/settings/-/blob/Neon/unstable/usr/lib/neon_update/neon_flathub.rb
This is currently blocked on creating a filtered flathub view that passes policy and legal qualification. That is driven by the Workstation WG currently.
This package has changed maintainer in Fedora. Reassigning to the new maintainer of this component.