relayd.conf man page question

[Alex Greif]

Hi,

while reading the relayd.conf man page, I found the following unclear paragraph:
...
RELAYS
 listen on address [port port] [tls]
    ... If the port option is not specified, the port from the listen on 
directive will be used.

My question: 
which *other* listen on directive is meant here? Or is the port mandatory?


Thanks,
ALex.