[8][9] It is a fork of the Firefox web browser with privacy-oriented changes, among which are a crowdsourced anti-tracking mechanism and an in-house search engine embedded within the browser, utilizing its own index of web pages to produce suggestions within the address bar dropdown menu rather than on separate pages.

[15] On 6 October 2017, Mozilla announced a test where approximately 1% of users downloading Firefox in Germany would receive a version with Cliqz software included.

Recommendations included news, weather, sports, and other websites and were based on the user's browsing history and activities.

"[16] According to the Firefox support website, this version of Firefox collects and sends data to the Cliqz corporation including text typed in the address bar, queries to other search engines, information about visited webpages and interactions with them including mouse movement, scrolling, and amount of time spent; and the user's interactions with the user interface of the Cliqz software.

It natively leveraged Cliqz's search engine, [ Human Web], and supported ad-blocking and other privacy features, like an optional built-in VPN with access to 25 countries.