rg3/youtube-dl — pull request #403 by FiloSottile (2012-08-19 23:24:37+00:00)
Title: Made the YouTubeIE regex verbose/commented

This might be useful both to regex beginners (our regex is incredibly complete of language features!) and to new contributors.
Pretty sure i haven't broke it ;)

See http://www.regular-expressions.info/freespacing.html and https://gist.github.com/2176911