I believe that comment to be incorrect. UPnP is using this port, but unofficially. The IANA port registration for 5000 is for commplex whatever it is, and it refers to two ports: 5000 and 5001. UPnP uses 5000 unofficially and does not use 5001.
> The Commplex is a communications package for communication with the NCUBE from Sun workstations.
Wait, all roads lead to Oracle?
So, uhm, this reminds me of STMPS and port 465. Read about it, and it's a sad state of affairs because of a blunder in managing that list. Funnily, mail providers and Cisco share that port (and no, not a TCP/UDP split, both are for TCP connections).
So who suggested to use port 5000 then way back? That's a serious question that is now my homework for this conversation.