Comment 8 for bug 516709

This diff shows, roughly speaking, how it could be done.

There are usability consequences that would need to be addressed at the same time. For example, once a branch has been made official for one package/distro, it becomes unwritable by its owner. This is unsurprising. Similarly, when looking at a branch that one owns but cannot write to, there needs to be some sort of clear indication. None of these are addressed in the patch.

Also, I hope this breaks some tests, but I don't really know.