You'll probably find that most of the requests you saw in Firebug are for the Inspector tool (built using YUI2).
The jshub.js file is the only 'tag' needed on a website (+ jquery if not already in use) and is designed to provide a 'hub' API for each vendors plug-in to query the data collected and send it on its way to a receiving server so only one file need be maintained as vendors come and go.
You'll probably find that most of the requests you saw in Firebug are for the Inspector tool (built using YUI2).
The jshub.js file is the only 'tag' needed on a website (+ jquery if not already in use) and is designed to provide a 'hub' API for each vendors plug-in to query the data collected and send it on its way to a receiving server so only one file need be maintained as vendors come and go.