Display name of the session's agent.
Perception debounce, in ms (the host's SceneDelta debounce).
Current element count on the board.
Friendly age of the last emitted delta ("2 s ago" / "—").
HTML-escaped JSON wrapped in token-tint spans (keys/strings/numbers/comments).
The "What [Agent] sees" perception popover: shows the most recent coalesced scene delta JSON (syntax-tinted) plus the perception-feed stats footer (debounce, element count, last-delta age, state of record). Anchored under the header button by the host; visibility is the host's concern.