This is a special publishing registry that describes
resources that represent important infrastructure
components to the VO registry framework. A primary purpose
is to provide a registry to discover other publishing
registries. A registry that wants to harvest all records
known to the VO can first harvest from this registry a list
of all known publishing registries (via the IVOA Registry
Interface for harvesting with set=ivoa_publishers). An
interactive interface allows publishing registry providers
to check their interfaces and make their registries known to
the framework. This registry also describes standard
protocols recognized by the IVOA.
