No IANA assignment; a listener here is VNC display :25.
IANA has 5915-5962 as Unassigned, and 5925 carries no service name. RFB's 5900+display rule makes it display :25, which is the kind of number a hypervisor reaches when it has allocated a couple of dozen guest consoles. Nothing else well-known squats on it.
Do not expose
Unauthenticated or weakly authenticated desktop access is the default failure mode of this port range — keep it on loopback or a management VLAN.
$ sudo lsof -nP -iTCP:5925 -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.