The system's more broad than deep, mostly. Lots of functionality covered, but for the most part, the abstractions aren't super-deep. My point was that someone

The system's more broad than deep, mostly. Lots of functionality covered, but for the most part, the abstractions aren't super-deep. My point was that someone can ramp up quickly on a portion of the system and have a vague idea of other parts of it, but "mastering" it covers too much code to do it in a reasonable time. Each plugin introduces special cases for the data flow, and the plumbing for that ends up running through the whole system.