Interface PickResult

Which PickingService.update produced the id buffer this pick read — the service's own update ordinal, starting at 1. A pick resolved a frame late is correct for the picture the user actually clicked on and stale for the picture now on screen; which of those an application wants is an application decision, and this field is what lets it tell (RFC 0005 §4).

Node.id of the front-most candidate under the point, or undefined for "nothing there". A string — the service owns the index↔id table and never leaks the integer it wrote into the texel, so the encoding can change (RGBA8 → r32uint on WebGPU) without a public break.

§96: this is an internal identifier (node-<n>, deliberately not user-controlled); an application echoing it into a DOM string is doing that on its own head.