This bug goes hand-in-hand with rAF-aligned pointer events (i.e. the getCoalescedEvents() API), and reflects the ability for a user agent to make a prediction about the position of future pointer movements. See - https://w3c.github.io/pointerevents/#predicted-events: Spec wording on the API - https://chromestatus.com/feature/5765569655603200 - Firefox also implemented it; despite the chromestatus page indicating otherwise Some new web platform tests check for the existence of this API, as was surfaced in the latest relevant WPT sync (270018@main).
<rdar://problem/117767174>