72 characters per line is a common standard for git commit messages. If you use vim, the syntax highlighting will nudge you to exactly that number.

https://tbaggery.com/2008/04/19/a-note-about-git-commit-mess...

72 characters is the standard limit for Git though. This convention has a long tradition from the text-mode days of email and Usenet in 80-column terminals/screens, where 72 characters allowed for the addition of a reasonable number of quoting levels (indicated by prefixing quoted lines with “>”), and/or for other line markers, before exceeding the screen width and having to reformat.

COBOL code seems to live in 72 columns, with the last 8 columns of a punch card were 'free for programmer use'.

Now I am wondering if somehow, some ancient COBOL limit ended up in git because every tool picked it up as convention from an older tool.