This is the ValueSet that contains all the codes in MDC Clock Resolution Types (http://hl7.org/fhir/uv/phd/ValueSet/MDCClockResolutionTypes) and MDC Clock Resolution Types (http://hl7.org/fhir/uv/phd/ValueSet/MDCClockResolutionTypes). E.g. what you have to deal with if you get resources containing codes in either of them