This is the CodeSystem that contains all the codes in SpecialValues (http://terminology.hl7.org/CodeSystem/special-values) and SpecialValues (http://terminology.hl7.org/CodeSystem/special-values). E.g. what you have to deal with if you get resources containing codes in either of them
Generated Narrative: CodeSystem 63461cdc-5d1b-4619-930e-2c74c910a25f-770
This code system http://hl7.org/fhir/comparison/CodeSystem/63461cdc-5d1b-4619-930e-2c74c910a25f-770 defines codes, but no codes are represented here