Lots of questions are definitely for Senior level engineers or even devops, i.e. - "HTTP 2 vs HTTP 1.1". There is nothing useful for junior level developer to know the difference of such low level things. Anyway, junior engineer will have no chance to decide what HTTP protocol to use in his project in Apple.

Another example - "NodeJS event loop internals". Nothing useful for junior, senior level+ is assumed, if you want squeeze out of maximum performance from NodeJS V8.