Agreed on the stdlib concept. I'm sure people are working on it, the benefit would be massive. Just the amount of mobile data transfer that could be saved by 1MB of software pre-distributed to all browsers would be huge.

I wonder if anyone is trying to do it based on the javascript integrity hashes. In theory, if you took the top 100 javascript libraries and established a blessed build pipeline that would produce reference builds that would be bundled to the browser, and if anyone loaded a resource with an integrity hash matching the browser's pre-installed versions, it could just load from disk instead. That would give people who can tolerate less frequent library releases the ability to use all that functionality without networking related page load costs, and would provide a fallback since CDN's could host the file anyway if the browser doesn't have it.