This DisplayString object names a port-list representing the destination ports a proxy Access-table entry covers, letting one rule match a named group of ports rather than a single port number. The desc ties correct operation of the entry to having a matching named entry present in the address-list table it references, so the list must be defined before use. For example, an administrator allowing proxy access to a web application spanning ports 80, 8080, and 8443 could define a port-list with those values and reference its name here instead of writing three separate rules.