This is the CodeSystem that contains all the codes in Endpoint Payload Types Code System (http://hl7.org/fhir/us/davinci-pdex/CodeSystem/EndpointPayloadTypeCS) and Endpoint Payload Types Code System (http://hl7.org/fhir/us/davinci-pdex/CodeSystem/EndpointPayloadTypeCS). E.g. what you have to deal with if you get resources containing codes in either of them