This is the ValueSet that contains all the codes in Treatment Reason (https://www.ehealth.fgov.be/standards/fhir/nihdi-terminology/ValueSet/be-vs-treatment-reason) and Treatment Reason ValueSet (https://www.ehealth.fgov.be/standards/fhir/nihdi-terminology/ValueSet/be-vs-treatment-reason). E.g. what you have to deal with if you get resources containing codes in either of them