This is the ValueSet that contains all the codes in Healthcare Provider Taxonomy (http://cts.nlm.nih.gov/fhir/ValueSet/2.16.840.1.114222.4.11.1066) and Practice Setting Code Value Set (http://hl7.org/fhir/ValueSet/c80-practice-codes). E.g. what you have to deal with if you get resources containing codes in either of them