> I don't swear that this is how GitHub actually works, but I've had knowledgeable friends swear up and down that it is.

All the details on how GitHub's infrastructure has evolved over the years are very publicly detailed in the GitHub engineering blog and in technical talks. There are no "secrets" or "rumors" here, all the information is one google search away. Perhaps you need to re-evaluate your priors on how knowledgeable your friends are.

- https://github.blog/engineering/architecture-optimization/in... - https://www.youtube.com/watch?v=Ri8hSZNKzu4 - https://github.blog/engineering/building-resilience-in-spoke... - https://github.blog/open-source/git/counting-objects/ - https://www.youtube.com/watch?v=DY0yNRNkYb0 - https://cursor.com/blog/git-at-any-scale