Some of cliqz services are already whitelisted in Firefox

Cliqz is one of the things you can add to your browser through testpilot, so it's not surprising cliqz is mentioned in that context. It also seems to be a "legacy" extension, thus maybe needing the exceptions.

https://testpilot.firefox.com/experiments/cliqz

Seems to be more likely than "Mozilla is secretly giving data to Cliqz and hopes nobody notices" to me. Unless someone has actual evidence to the contrary?

  "Mozilla recently announced that some of their German users downloading Firefox will receive a version that tracks some of their web activity, reporting it to Cliqz.com. In the wake of this development, which is pretty awful from a privacy perspective, I went spelunking into my version of FF to see if anything had been enabled already in my build."

Yep. Already listed in my build version 56 in the UK.