I was tinkering with writing my own .git parser recently, and I couldn't help thinking "this could've been an sqlite db".

I found https://github.com/chrislloyd/git-remote-sqlite as a way to achieve git-on-sqlite, which works by registering itself as a git "remote" helper.

Amusingly there exists a "Why SQLite Does Not Use Git" article (https://sqlite.org/whynotgit.html), but there is no corresponding "Why Git Does Not Use SQLite".