Yeah, but it's easy to skip once you know what it is and that you understand it already. For someone who doesn't, having it present may be vital.
In my opinion, the same is true of computing - as a mentor, especially when working with folks who don't come to programming from a "typical" background, there's a lot of basic context that has to be conveyed precisely because so much of our docs assume they can leave out all the stuff that "everybody knows".