This is the ValueSet that contains all the codes in Common Set of Symptom Codes (http://hl7.org/fhir/uv/symptoms/ValueSet/CommonSymptomCodes) and Common Set of Symptom Codes (http://hl7.org/fhir/uv/symptoms/ValueSet/CommonSymptomCodes). E.g. what you have to deal with if you get resources containing codes in either of them