Convert all Gnus groups to Thunderbird groups

Dear gnus experts,

I think we can agree that the best approach is to:

1. Export all groups to mbox format
2. use [1] to import these as groups in TB

[1] https://services.addons.thunderbird.net/en-Gb/thunderbird/addon/import=
exporttools-ng/

?

And I can use AI to generate elisp to do (1), but is there already a
well-tested solution to do it?

Many Thanks and Best Regargs,
Felix
=2D-=20
Felix Natter
debian/rules!