Thanks to @nodens!

Most of that is simply wrong nowadays.

That's a leftover of a long-defunct manual test suite automation project.
Right now it only creates noise during manual testing.

All tests that we can realistically automate include a link
to the corresponding issue.

Note that the upstream 91.5.0 release notes prominently say "For more on all the
new features in Thunderbird 91, see New in Thunderbird 91.0", and link to
https://support.mozilla.org/en-US/kb/new-thunderbird-91/, which seems much more
informative than
https://www.thunderbird.net/en-US/thunderbird/91.0/releasenotes/ for our
target audience.

So our users will still have a chance to get information about the 78 →
91 changes.

The shell snippet I'm fixing here was assuming check-mirrors.rb
would exit with a non-zero value if a mirror is not OK.
That's not the case.

The main use case for this contents is to be pasted on a pad that treats
Markdown as plain text.

ISO history is now publicly available.

Depending on the computer used by the RM, and on the available
isobuilders (lizard vs. iguana), the previous time estimates
may be either correct or vastly over-optimistic.

Let's set the RM's expectations more correctly.

Upgrade Tor Browser to 11.0.6-build1

Closes #18799

See merge request tails/tails!724

Fixes regression introduced with the obfs4proxy 0.0.12 final release:
tails/tails!724 (comment 183582)