No registration, no standard service — the number is free real estate that local software sometimes takes.
IANA lists no service for 5822; its neighbours 5820 (autopassdaemon, OpenText licensing) and 5825 are the nearest activity, and neither implies anything about 5822. No mainstream server defaults here. If your scan finds it, the answer lives in the process table of the host, not in any registry.
Expose with care
Unknown service. Identify it, then judge exposure on what it actually does rather than on the port number.
$ sudo lsof -nP -iTCP:5822 -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.