mjlawley and I spent some time discussing a use case that several national programs are trying to solve: I want to find all uses of a code that is in this value set, or that is mapped to a code in this value set. E.g. I have a set of LOINC codes or SCT. codes, but there's plenty of resources in my CDR using local codes that are independently mapped to the common national terminology.

The extension at https://build.fhir.org/ig/FHIR/fhir-tools-ig/StructureDefinition-select-by-map.html describes a way to solve this problem, and this task asks the committee to consider the use case and this task