This essay explains how Git works. It assumes you understand Git well enough to use it to version control your projects.

The essay focuses on the graph structure that underpins Git and the way the properties of this graph dictate Git’s behavior. Looking at fundamentals, you build your mental model on the truth rather than on hypotheses constructed from evidence gathered while experimenting with the API. This truer model gives you a better understanding of what Git has done, what it is doing, and what it will do.

https://codewords.recurse.com/issues/two/git-from-the-inside-out