The latest stable version for Firebug is 1.11.2 and the developer announces that it is compatible with Mozilla Firefox 17 through 20.Users already familiar with the beta builds for this release should already know that the highlight is the Closure Inspector that used to function as a separate extension (FireClosure).
Starting this revision, resetting the Firebug options also causes the aliases to be removed as a result. On the same note, FireClosure syntax has been added in the “help” command.
A full list of modifications for this release is available here. Firebug extension for Firefox can be downloaded from this page.