This is the CodeSystem that contains all the codes in TDDUI FR Core CodeSystem v2-0203 (https://interop.esante.gouv.fr/ig/fhir/tddui/CodeSystem/tddui-identifier) and TDDUI FR Core CodeSystem v2-0203 (https://interop.esante.gouv.fr/ig/fhir/tddui/CodeSystem/tddui-identifier). E.g. what you have to deal with if you get resources containing codes in either of them