http://hl7.org/fhir/StructureDefinition/version-specific-value|5.2.0

Provides an alternative value for the element carrying this extension that is the correct value for a particular range of FHIR versions other than the default value. This extension is found in contexts where a definition is applying to more than one version, usually defining extensions, and should only be used in context that clearly document how a cross-version definition is used. While there are no limitations to where this extension can be used, known uses are: StructureDefinition.context, ElementDefinition.type, ElementDefinition.additionalBinding and ...