I'm in the process of upgrading lp:mailman, or better known as
lp:~mailman-coders/mailman/3.0 to bzr format 2a. It's best not to
create branches of this locally for right now, and you will eventually
have to update your own local branches if you want to push a stacked
branch to Launchpad. Right now, Stephen's got the only stacked branch
on Launchpad that I can tell.
This will not affect Mailman 2.1 or 2.2 branches, only Mailman 3.0
branches. You will need bzr 1.17 at least, though the just released
bzr 2.0.0 is best. MacPorts has 1.17.
Ping me with any questions (though I'm still trying to figure out a
few things myself ;). This should be the last branch update for a
long while. The bzr folks tell me that 2a is long term supported.