There do not appear to be any tools for handling vc:rightsSet.
The transform uses either dcterms:rights and/or vra:copyrightHolder; the latter does not appear to be a property in the ontology.
In addition the transform inserts a value http://purl.org/rights/ + vc:rights/@type as the object of dcterms:rights, but what is this? http://purl.org/rights/copyrighted, for example, does not appear to be a web resource.