"add sponsored links to its browser in January 2018"
I said this was daft then.
Pocket is pointless and potentially invasive spyware (wanted pages saved on 3rd party server instead of users saving them).
As I've said frequently, they have lost the plot totally. On GUI, research, customisation, plug-ins etc. Still using Firefox 52ESR on desktop. The Mobile version is poo, though works. Very bad phone GUI though better than it was.