This is the ValueSet that contains all the codes in ISO Country two letter code (http://hl7.org/fhir/uv/emedicinal-product-info/ValueSet/country) and ISO Country two letter code (http://hl7.org/fhir/uv/emedicinal-product-info/ValueSet/country). E.g. what you have to deal with if you get resources containing codes in either of them