If you don’t want that default, overscroll-behavior is what controls it. You have likely experienced this behavior before and perhaps took it for granted that scrolling works like this on the web! If you are inside of an element that has its own scrolling (say it’s vertical) and you have scrolled down to the bottom of it, then by default, the next parent element up (maybe the page itself) starts to scroll in that direction.
The overscroll-behavior CSS property controls whether an element will use “scroll chaining” or not.
