I upgraded to Ubuntu 12.04 beta2 via
sudo do-release-upgrade -d and have identified a few... glitches and issues in the process/script, mostly from an end-user's perspective. There seems to more than one list that might fit, in the Ubuntu-devel- or perhaps Ubuntu-qa- or even Ubuntu-desktop- hierarchies.
I know about Launchpad, Brainstorm, BugSquad, etc, but am looking for the mailing-list where the people who develop this specific process discuss it.
In my experience, asking the person who knows the answer is much quicker than doing your own research. :)
(a retired computer guy with many years experience in the software development cycle, including OSs)