Unregistered high port with no known standard service.
50800 is above 49151 and therefore unassignable under RFC 6335, and Nmap's service database lists it as unknown. There is no product, protocol, or malware family durably associated with it in the primary references. A listener here was configured by whoever runs the host, and identifying it means looking at the process rather than the port.
Expose with care
No known protocol means no known security model; find the owning process before deciding whether it may be reached from anywhere.
$ sudo lsof -nP -iTCP:50800 -sTCP:LISTENSeen this on your network? Beige Box scans your Wi-Fi and shows every open port on every device — and its Ports tool links straight back here.
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Corrections or a missing port? Reply @rimrocksystems.