Or how about how they still replace pinned shortcuts in the new page with sponsored ads. Like the magical top left one that I don't even look at before clicking because it's a link to my mail.
Not to defend Firefox, but I believe Mr Robot is what caused them to make a visible toggle for experiments. Sadly it's not off by default, but once it's turned off, you don't really have to worry about it. That said, I never saw this VPN popup.
They pull this crap all the time and never learn their lessons.