If you must know why, I don't want promos for particular web properties in my browser. I find Pocket to be annoying conceptually (a service to help you carry around all the things you didn't and won't read—eww, no, no thank you), and I don't want to look at it every day. I don't want to have to Google to figure out how to disable it. I don't want my browser to come with nonsense I need to disable.
> You mean the single button that does literally nothing until and unless you click on it?
This must be the kind of mentality that leads people at FF to do silly things like mentioned on this thread, or having "just one button" for their acquired web property. That's the opposite of how great product minds think. Great product people think "how can I REMOVE this button?" Not "how can I get away with having it?"
My main complaints are that it's not more useful, though with some tweaks, I've made it just that.
https://www.reddit.com/r/dredmorbius/comments/5x2sfx/pocket_...
It needs more help than just CSS, but that's a start.