It outputs in the source code headers like so:
There is a compelling reason why going this route for plugins or themes meant for public release is a bad idea. It is because all the plugins and themes on your site will now have to use this specific version of jQuery. It is a bad idea to assume that other themes and plugins will work with this exact version without a hitch. Also, the CDN version of jQuery doesn't have the noConflict set, this means that other JS libraries will break.