We have in place the Content-Encoding:gzip header configuration in our servers. This header compress the size of all the files in the fly, saving a lot of bandwidth and time, strictly talking about loading/sizing times.
The gzip compression is enabled for all of our JS, CSS files.
It's also good to mention that we're continuously improving the loading time, size and response time of all of our system, and minimize our JS, CSS plugins files is already in our roadmap.