I'd love a detailed description of the politics and economics of adding this. Why are Firefox doing it, how does it relate to similar features in other browser

I'd love a detailed description of the politics and economics of adding this. Why are Firefox doing it, how does it relate to similar features in other browsers? If it leads to direct revenue, how? If there are relationship reasons for doing it, what are the forces at play? Just the actual background, not opinions on whether it is good or bad before understanding that background.