although in the context of version control, the term master simply refers to the gold master, a term borrowed from the recording industry which refers to the final mixed version of a recording, and does not have a corresponding slave.
Either way, I think “main branch” is easier to say, so it’s a win.
The term “master” is often used with the term “slave” in computing: https://en.wikipedia.org/wiki/Master-slave_(technology)
So it wouldn’t be odd to assume that git’s use of the term “master” also refers to slavery.
Either way, I think “main branch” is easier to say, so it’s a win.