Registered as TARGUS GetData — a vendor assignment with no public protocol behind it.
IANA assigns 5200 (TCP and UDP) to targus-getdata, with 5201-5203 registered to the same family as targus-getdata1 through -getdata3. There is no published specification and no widely deployed implementation, and scan data shows it very rarely. Note that 5201, one number up, is the iperf3 default and is far more likely to be what you actually meet in that range.
Expose with care
The registration tells you nothing useful about a listener here. Fingerprint the process before exposing the port.
$ sudo lsof -nP -iTCP:5200 -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.