being a device or mechanism that controls the operation of another mechanism or that establishes a standard (such as a dimension or weight)
being or relating to a master from which duplicates are made
In the realm of version control, the master branch tends to have special conceptual status as the branch you fork from and merge back to. It's not "main" like the main room of your house or main street in your city, it's the canonical branch which others are understood in relation to. It has nothing to do with slavery and renaming it to "main" obscures and confuses what was being communicated with the original name.
Yes "Master copy" was the terminology it was based on, but I'm more likely to hear and use "Original version" or "Original copy" today. I associate "Master copy" or to refer to old artifacts like Vinyl LPs, Film reel or document, with it's usage becoming more rare with the move to a digitized world. So I see its relevance & usage declining, esp. in Software where it's being proactively avoided in new technology.
But I don't believe "Master" is more intuitive nomenclature for new devs learning version control either nor a better representation for the naming the main branch where terminology is around a tree with branches being created from and committed to the 'main' single branch (i.e. trunk). When visualizing branches in a commit history it's shown and referred to as branches off the main trunk that deviates from the main branch at different commit points that may or may not return to the main branch like small roads off a main highway. The emphasis of branches being they're deviations or snapshots of a main branch's commit timeline, not in their state in which they're old copies of a main branch. The "Master copy" by definition does not change, it's a completed artwork, which is the opposite in CVS where it's always growing & changing with a tree of commits and often it's the branches which are snapshots of the main branch in labelled, well-defined points in its history.
Either way the terminology is definitely moving away usage of 'master' in new Software, so I don't fault their reasoning for deprecating existing naming and moving to more modern, intuitive & inclusive terminology.
Cambridge https://dictionary.cambridge.org/us/dictionary/english/maste...: an original version of something from which copies can be made
Merriam Webster https://www.merriam-webster.com/dictionary/master:
being a device or mechanism that controls the operation of another mechanism or that establishes a standard (such as a dimension or weight)
being or relating to a master from which duplicates are made
In the realm of version control, the master branch tends to have special conceptual status as the branch you fork from and merge back to. It's not "main" like the main room of your house or main street in your city, it's the canonical branch which others are understood in relation to. It has nothing to do with slavery and renaming it to "main" obscures and confuses what was being communicated with the original name.