The table below lists schemas in which records may be transferred. The
list is not exhaustive. None are required to be supported, and any other
schema (whether on the list below or not) may be supported in addition.
The Explain document lists the XML schemas for a given database in which
records may be transferred. Every schemas is unambiguously identified
by a URI and a server may assign a short name, which may or may not be
the same as the short name listed in the table below (and may differ from
the short name that another server assigns).