[esperent]

> symbolizes something completely positive: a master of some - usually artistically relevant - craft with followers that branched from the original (like the master branch in git).

Even in English, the term "master" branch has nothing to do with slavery. It originates from a master audio recording, usually just referred to as a master, from which other recordings are made.

[marliechiller]

It actually has the same origin as the parent poster of your comment:

Late Old English mægester "a man having control or authority over a place; a teacher or tutor of children," from Latin magister (n.) "chief, head, director, teacher" (source of Old French maistre, French maître, Spanish and Italian maestro, Portuguese mestre, Dutch meester, German Meister), contrastive adjective ("he who is greater") from magis (adv.) "more," from PIE mag-yos-, comparative of root meg- "great." The form was influenced in Middle English by Old French cognate maistre.

Source: https://www.etymonline.com/word/master