Some notes about Kriskowal's Q

I just finish reading the source code of Kriskowal's Q library and below are some notes (mainly to my future self).
First in case someone stumble upon this post, this library is a complete implementation of the very cool pattern promise/defer for javascript and node.

There are tons of stuff I haven't understood, I'll need to re-read that a few times. And I was thinking I could implement this library myself pretty easily, still a long way to go.