1st, Cliqz is majority-owned by Hubert Burda Media, an advertising and media company. You don't set the fox to guard the henhouse.
2nd, sending the user's complete browsing history to a 3rd party which is owned by an advertising and media company without telling the user was a terrible idea. It's simply mismanagement by the Mozilla Corporation.
https://blog.mozilla.org/press-uk/2017/10/06/testing-cliqz-i...
>This experiment also includes the data collection tool Cliqz uses to build its recommendation engine. Users who receive a version of Firefox with Cliqz will have their browsing activity sent to Cliqz servers, including the URLs of pages they visit.