Good teachers need to have the context of the student to know what level of explanation they need to give to satisfy the curiosity of the learner. (Also a potential reason that online programmatic learning is difficult as having the appropriate context to skip portions is incredibly hard to do with computers.)

General rule of thumb: The levels of the depth of explanations provided are generally proportional to the levels of understanding achieved.

Further understanding requires additional questions, research, and work.

https://ncase.me/nutshell/

For those interested in the ideas of annotations, inline footnotes, expandable text, additional context, stretch text, hovercards, etc., Nicky Case has recently released a new project called Nutshell (https://ncase.me/nutshell/) which has some fun user interface as well as code with which to play.