Comment by skydhash

> They do not write symbol docs mechanistically. They understand what the code is _doing_.

What the code is doing is important only when you intend to modify it. Normally, what's important is how to use it. That's the whole point of design: Presenting an API that hides how things happens in favor of making it easier (natural) to do something. The documentation should focus on that abstract design and the relation to the API. The concrete implementation rarely matters if you're on the other side of the API.