>Maybe "local/alien" might be a less pompous vocabulary to convey the same idea.

That is more alien and just as contrived. If you merge branches that you made, they're both local and "ours". You just have to remember that "ours" is the branch you are on, and "theirs" is the other one. I have no idea what happens in an octopus merge but anyway, the option exists to show commit titles along with markers to help you keep it straight.