Streaming displays an optional live preview from Blender behind the Controls interface. It is separate from the control connection: your app can control Blender without streaming, and streaming must first be configured in the add-on.
The app reloads the preview when Blender reports a new streaming URL or when the stream is restarted. For the best result, use a fast local network and keep the camera view and crop configuration correct.
If the preview is black, stale, slow, or unavailable, follow Streaming Troubleshooting. The preview does not replace the local UDP control server.