This is the ValueSet that contains all the codes in VBP Measure Population Type (http://hl7.org/fhir/us/davinci-vbpr/ValueSet/vbp-measure-population) and VBP Measure Population Type (http://hl7.org/fhir/us/davinci-vbpr/ValueSet/vbp-measure-population). E.g. what you have to deal with if you get resources containing codes in either of them