Mozilla is currently working to improve tracking protection feature, on that part, the Firefox team has replaced Tracking Protection with Content Blocking in Firefox 63. New Content Blocking feature that blocks third-party content, when turned on in normal mode can break or prevent sites from loading. Considering this, Mozilla is now trying to test Content Blocking features one by one on Nightly population, for now, since September 1st, FastBlock has been enabled by default.
What is FastBlock?
FastBlock is one of the Content Blocking features that improves page load performance by keeping a lid on the loading of slow trackers.
If you’re using Nightly, click on hamburger menu, click Content Blocking, you can notice slow-loading trackers turned on by default.
How to disable or turn off FastBlock in Nightly
If you face any issues with FastBlock, you can disable it by unchecking ‘Slow-Loading Trackers’ in Content Blocking UI Preferences. You can also turn if off by changing browser.fastblock. enabled preference value to false.
Mozilla is also planning to conduct a FastBlock Shield Study on Firefox 63 beta population to figure out the best way to deploy the feature.
The company has given more priority to Content blocking as it has been moved up to top in Privacy & Security section of Preferences.