Often times I have wondered what Javascript framework a site is using, and when I had time I would check the source of the page to try and determine this, but some sites are crafty or load time conscious and stick the framework inside a non likely named something I would recognize. Then I found WTFramework which was a nice bookmarklet that helped out. The one issue I had with it was that pages that had more then one framework would only show one of them.
So I made some changes to add suport for multiple frameworks. With WTFramework it would only find a single framework, if more then one was discoverable it would still show only one, I now append them all prior to showing. As an added bonus I added ExtJS as was requested in one of the comments on the post.
drag the link to your bookmarks bar and click on it whenever you want to know what frameworks are used.