Мне пришло вот такое письмо:
Hi,

mozilla is about to release an update of their firefox 2.0 release series
and the Ubuntu MozillaTeam [0] needs you to test the candidates builds
available in PPA [1].

The testing is done by running a test plan [3] and submitting the results
to the mozilla QA site [1]; in addition, just use the builds and look for
regressions while doing your daily work.

If you need help, just join #ubuntu-testing or #ubuntu-mozillateam on
irc.freenode.net and ask your questions.

Thanks a lot!

- Alexander

Note: We are looking for new testers on all supported ubuntu releases.
That's currently dapper, feisty, gutsy and hardy. In particular we have a
lack of dapper and feisty testers and your contribution on testing those
releases would be highly appreciated. So, if you want to help, but don't
have such a system installed (anymore), consider to setup a chroot or a
VM (try virtualbox [2]).

[0] - https://wiki.ubuntu.com/MozillaTeam/
[1] - http://mozilla.qa.ubuntu.com
[2] - virtual box instructions are https://help.ubuntu.com/community/VirtualBox
      and https://wiki.ubuntu.com/Testing/VirtualBox
[3] - Testplan: https://wiki.ubuntu.com/MozillaTeam/QA
Это действительно Mozilla или это розыгрыш?

если учесть, что все ссылки ведут на ubuntu.com, то и пришло оттуда, наверное

А откуда меня там вычислили?