This is the ValueSet that contains all the codes in eHDSI Data Absent Reason (http://terminology.ehdsi.eu/ValueSet/eHDSIDataAbsentReason) and eHDSI Data Absent Reason (http://terminology.ehdsi.eu/ValueSet/eHDSIDataAbsentReason). E.g. what you have to deal with if you get resources containing codes in either of them