This is the ValueSet that contains all the codes in Document Class Value Set (http://hl7.org/fhir/ValueSet/document-classcodes) and Advance Healthcare Directive Categories LOINC (http://cts.nlm.nih.gov/fhir/ValueSet/2.16.840.1.113883.11.20.9.69.4). E.g. what you have to deal with if you get resources containing codes in either of them