mozilla/butter — pull request #271 by jeremybanks (2012-05-04 21:10:48+00:00)
Title: [t1071] Dispatch "getHTML" event on Pages to allow modification of exported document

https://webmademovies.lighthouseapp.com/projects/65733/tickets/1071-allow-the-snapshotted-dom-to-be-manipulated

A single event with the html element that's about to be converted to HTML is probably enough.