The random classList polyfill at the bottom was a nice touch. As I scrolled to this bit I was initially like "oh this'll be nice they encrypted some of--oh. :("

My favorite bit was the "this detects the browser type and version" snippet that was copyrighted 2001. Nice!

I think the move to open-source the code was a ham-fisted way to get the "we're modifying copyrighted documents in flight" part past the lawyers. It's admittedly a pretty decent legal move.