Union of http://hl7.org/fhir/sid/icd-10 and http://hl7.org/fhir/sid/icd-10
This is the CodeSystem that contains all the codes in ICD-10 (http://hl7.org/fhir/sid/icd-10) and ICD-10 (http://hl7.org/fhir/sid/icd-10). E.g. what you have to deal with if you get resources containing codes in either of them