I’m a developer. I use main/release/dev for new projects, because it just sounds better and is more intuitive to me honestly. “Master” doesn’t make much sense. Like what’s so “master” about a “master branch”? It’s just the main branch everything gets merged into. It doesn’t “control” branches. There’s no “master/slave” relationship there. So again, “master” was never really intuitive to me.
Old projects don’t get relabeled, they stay master, cause relabeling the main branch could cause potential problems. That’s my two cents.