I wrote a script that is looking at the git log of a git repository, it tries to sum up how many commits per author/number of lines changed etc, when the author was active. This also gives some indication on the 'turnover rate' or whatever. (I know lines changed and number of commits is a very bad indication, but it is some indication)

https://github.com/MoserMichael/gittools/blob/main/git-whois...