Is this for sure built-in and not some extension? I don't have it.
Firefox
A place to discuss the news and latest developments on the open-source browser Firefox
its in beta
https://www.fakespot.com/privacy-policy
Internet or other electronic network activity (e.g., browsing history, search history, information regarding an individual's interaction with an internet website, application, or advertisement, and online viewing activities)
Category of Third Parties to Whom Personal Information is Sold and/or Shared: Advertising partners, Service providers
Just a snippet of the privacy policy. There's other bad stuff too like location tracking. It's also all ran through Google analytics.
So much for a privacy respecting Mozilla
And people thought Mozilla became an ad company when they bought the other ad company. Nope. I'm tracing it back to right here.
I hope that Ladybirdy gets something good happening. I simply having a another browser in this space would give Mozilla a good sanity check for their direction and values. Otherwise they're just kind of fumbling around.