this fall I worked with the core Git folks on writing an official data model for Git and it just got merged! I learned a few new things from writing it. https://github.com/git/git/blob/master/Documentation/gitdatamodel.adoc
@b0rk Reminds me a lot of https://alexwlchan.net/a-plumbers-guide-to-git/ which I found very helpful as well. Glad to see something like this become official! Thanks for this work 👍
A Plumber’s Guide to Git

Git is a fundamental part of many modern developer workflows -- but how does it really work under the hood? In this workshop, we'll learn about the internals of Git.