This is the ValueSet that contains all the codes in ValueSet message (https://www.ehealth.fgov.be/standards/fhir/mycarenet/ValueSet/eagreementmessage) and ValueSet message (https://www.ehealth.fgov.be/standards/fhir/mycarenet/ValueSet/eagreementmessage). E.g. what you have to deal with if you get resources containing codes in either of them