As the final step of consolidating all of the official Bazaar PPAs on Launchpad under one Launchpad team, the Bazaar Beta PPA formerly found at https://launchpad.net/~bzr-beta-ppa/+archive/ppa has moved to live under the main ~bzr team at https://launchpad.net/~bzr/+archive/beta. If you are a user and tester of Bazaar beta releases via this PPA, you will need to update your APT sources.list lines -  you can see the new sources.list lines under the “Technical details about this PPA” section at the above link.