This is the ValueSet that contains all the codes in FR Core ValueSet Unavailability Reason (https://hl7.fr/ig/fhir/core/ValueSet/fr-core-vs-schedule-unavailability-reason) and FR Core ValueSet Unavailability Reason (https://hl7.fr/ig/fhir/core/ValueSet/fr-core-vs-schedule-unavailability-reason). E.g. what you have to deal with if you get resources containing codes in either of them