Good point.

It was probably initially developed using a different VCS (e.g., svn), and when git became feature-complete that “svn” history was imported into git.

I really like nushell, which has more of a feel and ergonomics of a modern programming language without the idiosyncrasies of traditional shells (so it’s obviously not POSIX shell compatible).

One major downside is that it’s not yet stable, so breaking changes between releases are expected.