This is the CodeSystem that contains all the codes in Id Doc Media Type (https://www.ehealth.fgov.be/standards/fhir/nihdi-terminology/CodeSystem/be-cs-id-doc-media-type) and Id Doc Media Type (https://www.ehealth.fgov.be/standards/fhir/nihdi-terminology/CodeSystem/be-cs-id-doc-media-type). E.g. what you have to deal with if you get resources containing codes in either of them