This is the CodeSystem that contains all the codes in FR Core CodeSystem Marital Status (https://hl7.fr/ig/fhir/core/CodeSystem/fr-core-cs-marital-status) and FR Core CodeSystem Marital Status (https://hl7.fr/ig/fhir/core/CodeSystem/fr-core-cs-marital-status). E.g. what you have to deal with if you get resources containing codes in either of them