Apart from a fast browsing experience, Mozilla Firefox offers many privacy features. If you are not aware, the browser has a secret filter that prevents adult sites from showing up on your new tab page. The Adult Filter appears to work by checking URLs against a list of over 2,900 sites and filters them if a match is found. However, if you want to disable Adult Filter in Firefox, follow the steps below.
When you open a new tab, Firefox displays most commonly visited sites in groups. These sites are named as ‘Top sites’ and better known as ‘Highlights’. If the browser finds anything unsavory, it just prunes those sites out. This, it does by checking the URLs against a list of NSFW (Not Safe for Work) sites.
The filter, on the other hand, prevents tiles for adult sites from showing under Highlights/Top Sites section of the Firefox New Tab page. As such, whenever a user intends to visit a particular adult site or unknowingly bookmarks an adult or prohibited page, that page won’t appear on the New Tab page.
Enable or Disable Adult Filter on the New Tab Page in Firefox
By default, Adult Filter is Firefox is set to ‘On’ position. To disable it, you’ll have to copy the following line of text and paste it in the empty URL field of the Firefox browser-
After that, hit the Enter key and when prompted with a warning message, ignore it and proceed further.
Then, simply set the preference browser.newtabpage.activity-stream.filterAdult to false by double-clicking it or right-clicking it and choosing the ‘toggle’ option.
This value, when configured will disable the adult filter.
To enable it again simply change the value to ‘True’.
This browser feature was not developed for security reasons but for commercial partners that didn’t want to have their content associated with NSFW sites on the new tab page. Surprisingly, the filter has been in development since years but became largely visible only recently.