This is Net::Rendezvous, a set of perl modules to utilize DNS for service
discovery.  This method of service discovery is branded as Rendezvous by
Apple Computer.  More information can be found at:

http://www.zeroconf.org/
http://developer.apple.com/macosx/rendezvous/index.html

A list of register service types can be found at:

http://www.dns-sd.org/ServiceTypes.html