http://hl7.org/fhir/StructureDefinition/elementdefinition-maxValueSet|4.0.1

The maximum allowable value set, for use when the binding strength is 'extensible' or 'preferred'. This value set is the value set from which additional codes can be taken from. This defines a 'required' binding over the top of the extensible binding.
element_idtypes
Extension
Extension.extension
Extension.url
Extension.value[x]
Extension
Extension.id
Extension.extension
Extension.url
Extension.value[x]