Just a quick update. Thanks to Rob Campbell all necessary APIs for running Eventbug (Firebug extension for inspecting event handlers on a page) have been successfully backported into Firefox 3.6 (they are now part of Firefox 3.6b3pre).
So, you can happily use Eventbug even with Firefox 3.6!
Download Eventbug and Firebug 1.5.
We have made a great further progress with John J. Barton on a new extension for Firebug called Eventbug. Big thanks to Olli Pettay (smaug) for fixing #448602 + #506961 and providing new Firefox APIs that allow enumerating event listeners on a web page!
Notice that these APIs are available in Firefox 3.7a1pre (I hope they'll make it into 3.6) and you also need Firebug 1.5 to test it.
Update: all necessary APIs for Eventbug have been backported to Firefox 3.6b3pre.
So, see it in action!