[css-overscroll-scrollend-events] Content has no way of understanding whether it is being overscrolled or whether scroll has ended

When users scroll in an embedded iframes the events don't get bubbled outside of the embedded iframes to the embedder. However, if the embedded iframe has no scroller or has some scroller that has reached its extent the scroll might get chained to the embedder content and causes scroll there.

In this case the embedder content will get no input events (such as touch events that caused the scroll) but it keeps getting the scroll events. However, as oppose to the inner iframe which can get the touchend events to specify user is done interacting with the page, the embedder content has no way of determining whether the scroll has finished or whether maybe the content is being overscrolled.

We wanted to propose a new event type to support the behavior explained above. We started an incubation over here.

I wanted to move this under WICG but let me know if you prefer somewhere else.

No repository files or tests are identified in the issue. Start by reading the linked overscroll-scrollend-events incubation and the CSSWG discussion; the work would need an agreed event design and placement before implementation can be considered done.