This is the CodeSystem that contains all the codes in C4DIC Extended Coverage Class (http://hl7.org/fhir/us/insurance-card/CodeSystem/C4DICExtendedCoverageClassCS) and C4DIC Extended Coverage Class (http://hl7.org/fhir/us/insurance-card/CodeSystem/C4DICExtendedCoverageClassCS). E.g. what you have to deal with if you get resources containing codes in either of them