The original copyright holder claims on reddit[0] that it was forked, and there doesn't seem to be any implication of buying the rights to the software.

[0] https://www.reddit.com/r/opensource/comments/roa9xz/microsof...

This comment shows they've done it to other pieces of software, including things like… CUPS: https://news.ycombinator.com/item?id=29684567

For some reason I doubt they've bought the copyright to CUPS.