14 DAY TRIAL // An essential part of new features developed for Mozilla Firefox is the Nightly build of the browser, which allows Mozilla to play with all kinds of improvements that can be tested by users before they are officially released to all users.
The Nightly build of Firefox is updated on a daily basis, and it goes without saying that some of the features that are released to users in these builds don’t necessarily make it to the stable channel.
This is because not everything runs exactly as anticipated, so Firefox Nightly is a platform for testing features that may or may not be released to users at some point in the future.
This is actually the main reason why running Firefox Nightly is not recommended on production devices. So no, you shouldn’t use this app as your daily driver, as any potential issue could break down the entire experience on the computer. And the likelihood of problems is obviously pretty high given that Firefox Nightly is supposed to be used for all kinds of experiments.
More recently, Mozilla has started testing a new Settings page of the experiments that it rolls out in Nightly, allowing users to control them from the configuration screen of the browser.
Not all features that are available in the Nightly build of Firefox are displayed here, but Mozilla wants to give users the possibility of enabling some of them easier if they ship disabled.
This new experiments screen is available in the most recent Nightly build and needs to be enabled manually – this is a sign that Mozilla doesn’t consider it ready for public testing, so it’ll probably take a while until it gets the go-ahead to be released to all users in the same channel of Firefox.
Enabling it is actually pretty easy, as noted by GHacks, pretty much because it all comes down to enabling a flag in the Nightly build of Firefox.
The first you need to do is make sure that you are currently running the most recent version of Firefox Nightly. I tested the whole thing in Firefox 79.0a1 (2020-06-23) (64-bit), so if you’re running at least this build of the browser you should be perfectly fine.
Once you launch the browser, type the following code in the address bar to launch the flag configuration screen:
about:config
In the search box at the top, type this code to find the flag that lets you enable the experiments screen:
browser.preferences.experimental
By default, the flag is set to False, which means it’s disabled, so click the toggle button to switch it to True. At this point, the new experiments screen in the Settings menu should be enabled and you should be able to view all the features that are available for testing in the most recent Nightly build.
If you want to disable this screen, it’s enough to just follow all the steps mentioned above, only that the flag must be set to False.
At this point, the whole thing is still in its early days, so it could take a while until it’s enabled for all users. Of course, while it could be brought to the stable version of Firefox, it might actually make little sense since this feature is supposed to allow users to play with experimental features.
The stable Firefox version is built to offer the smoothest experience regardless of the platform, so trying out experimental ideas isn’t necessarily the purpose for this version. For now, however, the whole thing remains hidden under a dedicated flag in Firefox Nightly.