a string
that identifies the schema version for
the given component.
The format of the version string is arbitrary. No meaning
should be attached to it, unless an implementing service
defines one. If no version can be determined, an empty
string
may be returned.
Clients may assume that all instances of a schema with the
same version are identical. The converse is not true.
In particular an implementation may return the same version
string for all schemas it supplies (i.e. return a version for
the complete schema, including all components)