This is the ValueSet that contains all the codes in HPDocumentType (http://hl7.org/fhir/us/ccda/ValueSet/2.16.840.1.113883.1.11.20.22) and HPDocumentType (http://hl7.org/fhir/us/ccda/ValueSet/2.16.840.1.113883.1.11.20.22). E.g. what you have to deal with if you get resources containing codes in either of them