Origin of the embedded TeXbrain editor. Used BOTH as the postMessage
targetOrigin (host -> guest) AND as the allowed event.origin (guest -> host).
Never '*' — the bridge is first-party app-to-app, so origins are pinned
(EditorBridgeClient rejects any message whose event.origin !== this value).
Origin of the embedded TeXbrain editor. Used BOTH as the postMessage targetOrigin (host -> guest) AND as the allowed event.origin (guest -> host). Never '*' — the bridge is first-party app-to-app, so origins are pinned (EditorBridgeClient rejects any message whose event.origin !== this value).