Unregistered with IANA and not the default for any well-known software.
IANA lists no service for 10616, and Nmap's database calls it unknown, open on about 0.04% of scanned hosts. There is no protocol the number implies. Anything answering is application-specific, so identify it from the process or the banner rather than from a port list.
Expose with care
No registration means no assumptions about what the service does or whether it authenticates. Identify it before exposing it.
$ sudo lsof -nP -iTCP:10616 -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.
Get Beige Box →also available as JSON · Markdown
Corrections or a missing port? Reply @rimrocksystems.