Git from the inside out

"Git is built on a graph. Almost every Git command manipulates this graph. To understand Git deeply, focus on the properties of this graph, not workflows or commands. To learn more about Git, investigate the .git directory. It’s not scary. Look inside:"

checkout -> Git from the inside out

Mary Rose Cook wrote a superb exposition of git's internal structure. The cryptic stuff like FETCH_HEAD and bare clones can be easily understood.

-- Thanks from: https://source.quora.com/Git-from-the-inside-out-graphically-superb