Comment by mzzter

I like to go to the first few commits of some repositories to see how the initial proof of concept was implemented. Docker was one that surprised me. Turns out that the core of it was mounting some folders with union fs and providing an API to track its location and status [1].

[1] https://github.com/moby/moby/blob/a27b4b8cb8e838d03a99b6d2b3...