Interesting - and a very good job given what you have to work with. Surely its incredibly brittle, though? As soon as they release a new version of Gmail it's going to fail.
But then, I suppose that's how most Chrome extensions work.
But then, I suppose that's how most Chrome extensions work.
However, it's even worse than you think. It's making a lot of references to minified/obfuscated names. Things like $('.nH.hx'). When I was working on a gmail script[1] a year or two ago, many of those were changing every few hours.
It's solvable, but not easy.