What minifier was used to generate the official JQuery “minified” version?

Question

I need to edit the current JQuery library 1.4.x (and completely rename the JQuery \"object/function\") in a high conflicting environment.

My question is, with what

Answer 1

I believe it is Google Closure: Google Closure minifier online?

Answer 2

According to the offical release notes it is the Google Closure Compiler.

UPDATE:

As of jQuery 1.5 they are using UglifyJS (ticket) instead of the Google Closure Compiler.