I’ve started using Google reader again and came across the truly brilliant Dust Me Selectors extension (good work brothercake). It’s aim is to report on the CSS redundacy on your site. I hooked it into our selenium test suite and set it to run on page load. Selenium closes the browser when done and deletes the profile directory so I had no way of accessing the data (stored in preferences in a json string). A quickly hacked the js

var oClipboard 	= Components.classes["@mozilla.org/widget/clipboardhelper;1"].getService(Components.interfaces.nsIClipboardHelper);  oClipboard.copyString(str);

I set a pause on the last selenium test and then chose view saved data from the Dust Me Selectors context menu.  I then had the full report in html on my clipboard and could let selenium continue with it’s profile cleanup.