Archive for February, 2016

Firebug 2.0.14

Monday, February 8th, 2016

The Firebug team released Firebug 2.0.14. This is a maintenance release ensuring compatibility with latest Firefox releases.


Firebug 2.0.14 is compatible with Firefox 30 – 46

Firebug 2.0.14 fixes the following issues: 7954, 7964, 7961, 7956.


We blogged last year about our effort to unify Firefox Developer tools and Firebug and we’ve made good progress since then. Now it’s time for the next step read more


Please post feedback in the newsgroup, thanks.

Jan ‘Honza’ Odvarko


Merging Firebug into the built-in Firefox Developer Tools

Monday, February 8th, 2016

We blogged last year about our effort to unify Firefox Developer tools and Firebug and we’ve made good progress since then. Now it’s time for the next step…

We’ve been working hard on refactoring existing Firebug 2 features and extensions so, they work together with new Firefox built-in developer tools and support recent platform changes like the new multi-process architecture (a.k.a ‘e10s’).

Many Firebug features have already been added to the built-in tools, and several Firebug extensions have been ported to be Firefox addons:


We’ve been also working on a follow-up Firebug 3 (a.k.a extension that allows us to test features before we land them in Firefox. Firebug 3 contains further popular Firebug features like XHR Console Inspector (aka XHR Spy) and a DOM panel for Document-object-model inspection.


The best part of this extension is a new Firebug theme (in addition to existing Light and Dark themes) so, Firebug users can feel like home when switching into Firefox built-in tools.

Beta version of is available for download.


Note that the XPI is not signed and so, you need to flip xpinstall.signatures.required to false to allow installation.


Here is a screenshot showing Firebug theme in action:

DOM panel
(yes, this is built-in devtools toolbox, not Firebug!)


The work on the theme has helped us support existing Firebug users, and also make sure that theme APIs are extensible enough and ready for developers who want to build themes.


Firebug 2 doesn’t work in multi-process browsers (i.e. e10s) and converting it is too complex, it will stop working when e10s is activated in Firefox.

We want to be ready when Firebug 2 stops working and we have come up with the following plan.

  • Integrate all Firebug 3 features into Firefox built-in tools and forward all Firebug users to it.
  • Replace Firebug 2 by releasing Firebug 3 (on AMO) only if we have to deliver any critical features missing in Firefox developer tools in an extension.


We are currently working on porting XHR Inspector (bug 1211525), DOM panel (bug 1201475) and Firebug theme (bug 1244054).

Don’t worry if you want to run multi-process browser (DevEdition or Nightly) now. We have introduced transition path that will allow you to move from Firebug 2 to built-in DevTools. See the following screenshot (Firebug 2.0.14).

Firebug running in multi-process browser message

This notification message appears if you are running Firebug 2.0.14 in multi-process Firefox. It allows to open built-in Developer Tools or choose to disable e10s and keep Firebug.

Happy debugging!


Jan Honza Odvarko (Firebug Working Group)
Joe Walker (Firefox Developer Tools)