ValueConstraints as used by the FIeldQuery of the Entityhub currently support only a single value. This is also true for ReferenceConstraint as this internally uses ValueConstraint and only sets the data type to URIs.
This will allow to query for Resources that do have any of the parsed values (e.g. searching for Entityies of rdf:type dbpedia-ont:Person or dbpedia-ont:Place)
In addition the new "mode" parameter will allow to treat multiple values as "any" (at least one) or "all". The default will be "any"