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