Inspired by this topic I asked the question on how to read documentation [1] (I searched for it, it didn't seem to be there). I really could improve my documentation reading skills but don't know where to effectively search for it (I normally search on HN for quality content on technical topics).
I assume the [] in the jquety children case would mean optional parameter but won't in other documentation. It tends to depend on the language and the library authors, often you have to figure it out yourself.