Mozilla launches set of experimental features in Firefox Dev

Martin Brinkmann
Aug 14, 2015

If you are running the Firefox Developer Edition on desktop or Firefox Aurora on Android, you may have noticed a couple of changes after today's update.

Mozilla added several features to those pre-beta versions of Firefox that were previously only available in Nighly builds of the web browser.

Electrolysis, Firefox's upcoming multi-process system is advertised on first run right away. Users receive a prompt about it and may enable it in Firefox Dev if they want to.

The feature will improve the browser's responsiveness and in the long run security. The main drawback is that many add-ons are not yet compatible with Electrolysis. You can check the Are We e10s Yet website for a list of add-ons that are compatible.

The site lists 118 broken and 569 untested add-ons currently, among them popular extensions such as NoScript, Ghostery, Adblock Plus and even Mozilla's own Lightbeam for Firefox add-on.

More interesting that from a user perspective is the modified private browsing mode. You can enable private browsing with the shortcut Ctrl-Shift-P or via the menu by tapping on the Alt-key and selecting File > New Private Window from it.

firefox private browsing

The new private browsing interface has changed. It lists data and information that Firefox will forget once the mode is exited and which information it will keep.

The main new feature is Tracking Protection however.  Tracking Protection blocks known trackers automatically when you are using private browsing mode in Firefox. This improves the privacy of users in that mode and has the added benefit that pages load faster in the browser.

Tracking Protection is automatically enabled. It should not be confused with an ad-blocker, as it does not block ads but only a selection of known tracking servers.

Users who don't want to use the feature can turn it off on the private browsing start page.

The third change enforces the signing of add-ons in Firefox Dev. Installed add-ons that are unsigned are disabled automatically, and the installation of unsigned add-ons is blocked by the browser as well.

firefox block unsigned addons

The main idea behind the enforcement is to block malicious add-ons from being installed in Firefox as they cannot be signed.

Firefox Dev and Nightly editions have an override switch to enable the installation of unsigned add-ons, something that Beta and Stable versions won't support.

Additional information about all three feature additions are provided on the Mozilla Blog.

Mozilla launches set of experimental features in Firefox Dev
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Mozilla launches set of experimental features in Firefox Dev
Mozilla launched a set of experimental features in Firefox's Developer edition, namely Tracking Protection, Electrolysis and signed add-ons.

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  1. DonGateley said on August 15, 2015 at 10:39 pm

    They want to update my dev install from 41.0a2 to 42.0a2. I have blocked that because of earlier posts here relating to not being able to disable unsigned add-on blocking with 42. Now here I seem to get it that the inability to disable blocking does not apply to 42.0a2 or any dev build, just stable builds. Is that correct?

  2. Pierre said on August 15, 2015 at 5:22 pm

    Thks, very interesting

  3. EPB said on August 15, 2015 at 7:01 am

    Firefox totaly crap. I am using Epic Privacy Browser

    1. DonGateley said on August 15, 2015 at 10:33 pm

      Thanks for sharing. :S

    2. Jeff said on August 15, 2015 at 3:31 pm

      All that browser does is incorporate common privacy extensions, all of which can be enabled in Firefox or Chrome anyway. Epic is just Chrome with some extensions and a new name.

      I have HTTPS Everywhere, Ghostery, Privacy Badger and Canvas Blocker and a few others enabled in Firefox, as well as Duck Duck Go search and have the same privacy features you do.

      1. Jeff said on August 15, 2015 at 7:09 pm

        all of those features are easily enabled in Firefox.

        Epic doesn’t “need extension” because the extension is just built in. No functional difference.

      2. EPB said on August 15, 2015 at 6:11 pm

        Epic Privacy Browser:

        no need extension
        no webrtc leaks
        no canvas fingerprintings
        no history

  4. Ro9bert said on August 15, 2015 at 5:16 am

    With version 40.0.2 I have seven extensions yellowed out telling me that they could not be verified for use in Firefox. If the next update kills them, I am officially through with Firefox and heading for Palemoon. LastPass, Click&Clean, Adobe Acrobat-Create PDF and WordWeb are just a few of them yellowed out.

    1. Jeff said on August 15, 2015 at 3:27 pm

      Not sure what is up with yours, but I have LastPass working fine (not yellowed) in 40.0.2 (32-bit). My lastpass version is 3.2.16.

      When you say yellowed out, are you saying the extensions are disabled? I have Privacy Badger yellowed out in 40.0.2, but it is still working and enabled. this is just Mozilla’s new security feature that warns if an extension is unsigned.

      IMO, this is a good thing, and should have been done a while back. I think that they should give the end user an option to use an unsigned extension, but I don’t think this is something to abandon Firefox for. They are doing this to combat the massive number of malware extensions that currently have free reign to take over the browser.

  5. Monessem said on August 15, 2015 at 5:02 am

    good step from Mozilla

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