I was trying to make something like this post a couple of years back and used custom headers, even made this repo with a few zeroes with no salt on the commit message and no shenanigans in the files: https://gitlab.com/pedroteosousa/teste/-/commit/000000005093...

I have this ugly code that finds the salt given the target hash, and another that actually creates the commit given the salt. Is not very useable, but I'll leave it here for anyone that finds it interesting: https://gitlab.com/pedroteosousa/useless-git-tools/-/tree/ma...