I don't know about the kernel specifically, but most large code bases are modular. There's probably a small set of core kernel functionality that provide servi

I don't know about the kernel specifically, but most large code bases are modular. There's probably a small set of core kernel functionality that provide services for everybody, and then specialized interfaces for each of the driver types. I would guess that few people are familiar with the entire structure. Most probably know the core interfaces and the design of the subsystem where they mostly work, like wireless drivers.