Sorry, documentation for this Enumservice is still missing. Documentation will be updated continually as time permits (yes, i have a day job, too). In the meanwhile, i suggest you to check out the list of Enumservice registrations, and take a look at the respective RFCs there.
If the Enumservice is an experimental one (starting with "x-") then it's very unlikely that any official documentation is available. In addition, there are also a few non-experimental Enumservices in the wild which are not registered (means they neither start with "x-" nor are they registered with IANA.