> On a more technical and pedantic level, having a "master" branch really doesn't make any sense without slave branches.

The reason master branches are called master branches is as an analogy to a music/record "master", which means "the original, the truest, the canonical".

(In an analog world where every copy necessitated deterioration, there was a need to say "this is THE version").

So git master branches meant the same thing: canonical. That's why the name "makes sense" even though there are no slave branches.

Just adding this here out of a sense of duty for historical accuracy, and not commenting on the name change itself.