If you search for Thunderbird in GNOME Software you will see two Thunderbird entries, who should be this reported to, the GNOME Project or Fedora? One of the entries links to Fedora registry and Flathub, the other entry only links to the Fedora registry.
EDIT: I have been trying to find differences in between the two Fedora registry versions, one says “Version Stable”, the other one says “148” and the Flathub version says “140.9.1esr”.
Perhaps one is a extended support release and the other one isn’t? Perhaps this could not be called a bug, but it is very confusing, at the very least in the title they should name them different, if that is what is happening one entry should have the esr tag, although that is going to mean nothing to a new user anyway.
Who writes title, description and version in this case? Fedora? GNOME? Mozilla?
This is an unfortunate situation, where Flathub provides the Flatpak under the org.mozilla.Thunderbird app id, whereas Fedora provides it both under the old org.mozilla.Thunderbird ref, as well as under the new net.thunderbird.Thunderbird ref as well.
The CLI provides some explanation:
$ flatpak install thunderbird
Looking for matches…
Remotes found with refs similar to ‘thunderbird’:
1) ‘fedora’ (system)
2) ‘flathub’ (system)
Which do you want to use (0 to abort)? [0-2]: 1
Similar refs found for ‘thunderbird’ in remote ‘fedora’ (system):
1) app/org.mozilla.Thunderbird/x86_64/stable
2) app/net.thunderbird.Thunderbird/x86_64/stable
Which do you want to use (0 to abort)? [0-2]: 1
Info: app org.mozilla.Thunderbird branch stable is end-of-life, in favor of net.thunderbird.Thunderbird branch stable
Replace? [Y/n]:
I don’t know the explanation behind Fedora choosing to ship Thunderbird under a different app id (probably esr and non-esr editions, as mentioned by you), but the experience in GNOME Software is less than stellar.