It Depends On What You Mean By “Sale of Data”
Firefox have long had a promise to never sell your personal data and “to protect you from many of the advertisers who do. Firefox products are designed to protect your privacy.” but that is no more. Now they promise that they do not “sell data about you (in the way that most people think about “selling data”), and we don’t buy data about you.” This is a fairly major change, which they justify by claiming that the legal definition of sale can be interpreted in so many ways that they worry they could unintentionally break their old promise. This seems a fairly specious excuse, there may be legal different definitions of sale but at heart they would all have reasonably similar and Firefox neglected to provide any examples.
Along with this new promise comes new terms of use, which you can see quoted below. This change is a far cry from protecting their users and is more along the lines of something you would expect from Meta. There are more questionable updates, along with some highlighted replies from Firefox users in the post at Ars Technica. How the mighty have fallen.