What Tools Does Google Use to Manage Their JavaScript?

I was reading this article and came across this:

Gmail engineer Adam de Boor surprised the开发者_C百科 audience by noting that the company's Gmail service was written entirely in JavaScript, and that all of its code, around 443,000 lines worth, was written by hand.

Assuming he wasn't talking about GWT, that's a ton of JavaScript code. It made me wonder how they manage it all.

Some questions: What do they use to write it all? (I'm guessing emacs or vim or similar)

What do they use to package and test it all? I know of sprockets for packaging it all up, but is there something else?

What do they use to debug? Firebug is nice and all, but I have some beefs with it...

Google uses a home-grown javascript compiler to optimize the hand written js code before sending it to the client. See http://code.google.com/closure/compiler/