What is the Chrome Dev Tools “Hit Test” timeline entry?

Question

When looking at a Chrome Dev Tools timeline I noticed that there was a "Hit Test" entry every time somethings happens:

Does anyone know what it is? I've done my googling, but am still at a loss.

Thanks!

Answer 1

A hit test is how a contact (mouse/touch) event is checked to see what it "hit" in the DOM.

https://www.chromium.org/developers/design-documents/compositor-hit-testing describes some of this.