This is the ValueSet that contains all the codes in Medication request course of therapy codes (http://hl7.org/fhir/ValueSet/medicationrequest-course-of-therapy) and Medication request course of therapy codes (http://hl7.org/fhir/ValueSet/medicationrequest-course-of-therapy). E.g. what you have to deal with if you get resources containing codes in either of them