```ctrl-pgup``` typically moves to the next browser tab, which is why I used alt for this.

With three pages visible, it puts page 3 at the top, so you see pages 3 to 5. I guess you could argue to have page 2 at the top (exactly one page down), or page 4 ("about one screen down, but at an exact page boundary"). I don't have a strong opinion either way, and am fine with the current behavior too. I'm not sure I would often zoom out that much, as that makes pages barely visible. Even a single page is often small when fit on a screen.

The point of this feature is to scroll down at a page boundary, as I find it tiresome to adapt to the page boundary to constantly appear at a different place on the screen.