Here are some random domains taken from the Caddy Forum threads:
https://lastfree.space/.git/HEAD
https://www.aspecthq.com/.git/HEAD
Those people are unaware of serving their git (or .env files or other secrets) over the internet, probably because are used to other webservers that just block this behaviour by default.
And it's ok to not do or be like the others, but this should at least be mentioned in the docs.