I like optional, it seems like there's no reason there couldn't be an additional flag set at the time of branch. You do kind of know who branched though because

I like optional, it seems like there's no reason there couldn't be an additional flag set at the time of branch. You do kind of know who branched though because aren't they going to have the first commit on that branch? But perhaps what you'd be looking for is something like the tag system where one could bring up all the branching at once in a big list...