The 554 RTSP restream thing is something I see a lot in badly configured NVR setups. Many NVRs are configured to restream the cameras they watch, the idea being that only the NVR watches the camera's feeds directly to reduce the CPU load on the relatively weak CCTV cameras - the beefy NVR server can restream to many more clients instead of them all talking to the camera individually.

There are so many of these tools that simply re-stream the RTSP CCTV feed with no support for using any sort of authentication though - the expectation is you configure firewall rules appropriately so only the "correct" devices can view the feed on the open port.