I use it on iOS daily and there’s no ad blocker. The page you linked only mentions tracking blocking. If you actually have ad blocking enabled, I’m sure a lot of us would love to hear how you did it.
It was originally pitched as a "distraction blocker" and it works in two modes. As a browser and as a content blocker, if you enable it in Safari's extension settings. I've still got it set up as a content blocking Safari extension (you find that in Settings -> Apps -> Safari -> Extensions) and it still seems to be blocking ads for me. Maybe not as many as it once did, but I just turned it off to see, and that made an unpleasant difference.
I think I've been using it for 10 years (or so) now. It's my favorite thing Mozilla has done on iOS.
Mozilla advertised Firefox Focus to block tracking and ads before. And it blocks some ads.[1] It is not possible to block tracking effectively without blocking some ads at least. They could have stopped to advertise ad blocking because people who wanted ad blocking wanted better.
I think I've been using it for 10 years (or so) now. It's my favorite thing Mozilla has done on iOS.