New in CSS Selectors Level 4 is the ability to optionally pass a selector list into :nth-child() and :nth-last-child().
For example, :nth-child(2 of .highlight) selects the second matching element that has the .highlight class. Put differently: out of all children with the class .highlight, select the second one.
Agreed. Here is a video titled "How a simple Django application works" that is 8 minutes long. It has 29 likes and 27 dislikes. It's a pretty poor quality video, in my opinion.
I think if that was ever said by a core member, it was stated as a goal, not a for sure thing. I believe I've only ever heard it as speculation / wishful thinking.