browser
I see a comment below from a Mozilla employee stating that "there is limited public information available about this deal", and claiming that the best quote is in an article that contains a paraphrase from an email from another Mozilla employee saying that Pocket didn't pay for placement.
When a non-profit gives prominent placement to a for-profit company, there are many ways for money to change hands beyond straight up payment for placement. I think we are owed a clear explanation of the Mozilla-Pocket deal.
Pocket was added to Firefox because Mozilla wants the extra revenue from partnering with Pocket.
Firefox is a niche product that appeals to the privacy-consciuos. Stuff like Pocket and Telefonica/Hello basically eliminates its reason for being.
I have Firefox as my main browser now, but I won't keep it around for long if I have to swat down new marketing integrations in every new release.