I’m pleased to announce that the initial version of Firediff is now available.
Firediff is a Firebug extension whose goal is to provide additional insight into the changes that are being made to the components of the page. As a 0.1 release this is effectively a preview of the final goals of the project. Many of the end goals such as diff generation, undo/redo functionality, and change persistence are still in the infancy.
Firediff currently requires a recent build of Firebug, with a strict requirement of at least version 1.4.