Mozilla Firefox 67 will introduce a new policy that will block extensions from running in private windows.

The reason is as simple as it could be: since extensions sometimes need to access your data to work correctly and the private browsing mode is supposed to be, well, private, Mozilla believes that blocking add-ons by default can help guarantee no traces are left behind.

And to do this, the company has decided to block all extensions by default in private windows, unless you specifically allow them to run.

This change continues Mozilla’s efforts for increased privacy in Firefox privacy, and is likely to win the hearts of many users who believe this is the correct approach and do not agree with the data collection that happens in other browsers.

Needless to say, the best of all is that Mozilla will still allow users to decide if they want extensions to run in private windows or not, as dedicated controls would be offered in several parts of the UI.

The feature is already being tested as part of the Nightly version of Firefox, so you can already try it out right now if you install Mozilla’s testing browser.

Beginning with Firefox 67, whenever you open a new private window, you’ll be provided with a notification that extensions are blocked.

“Change to extensions in Private Windows. Any new extensions you add to Nightly won’t work in Private Windows unless you allow this in the settings,” the notification reads – the Nightly part will probably be replaced with Firefox once version 67 ships.

A similar warning is placed in the configuration screens of extensions in Firefox browser.

“Nightly is changing how extensions work in private browsing. Any new extensions you add to Nightly won’t run by default in Private Windows. Unless you allow it in settings, the extension won’t work while private browsing, and you won’t have access to your online activities there. We’ve made this change to keep your private browsing private.”

Firefox 67 won’t come with a setting to let you enable extensions in private mode browser-wide, but instead you’ll have to set the new permissions individually for each add-on.

There are two ways to do this.

First and foremost, you can enable a specific extension to run in private windows when installing them. The notification that shows up when installing extensions makes it possible to “Allow this extension to run in Private Windows,” so you can quickly enable this behavior and that’s it.

If you want to configure extensions that are already installed, you need to head over to the add-ons manager in Firefox 67. You can simply type about:addons in Firefox to see the installed extensions.

Enabling them to run in private windows comes down to simply expanding the options of each extension and then checking the setting that reads “Run in Private Windows > Allow.” By default, this option is set to “Don’t Allow.”

As per TechDows, you can enable all extensions to run in private windows by modifying a dedicated flag in the about:config section. The flag is called:



extensions.allowPrivateBrowsingByDefault



According to the company’s release calendar, Mozilla Firefox 67 should be released to users on May 14, 2019, so the developing team still has some two months to make sure that everything is working as expected. If you install Nightly, keep in mind that this is an experimental browser and some things may not work exactly as expected.