This is the ValueSet that contains all the codes in Identifier Type Code (https://nrces.in/ndhm/fhir/r4/ValueSet/ndhm-identifier-type-code) and Identifier Type (https://nrces.in/ndhm/fhir/r4/ValueSet/ndhm-identifier-type-code). E.g. what you have to deal with if you get resources containing codes in either of them