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

The specific element to use in the referenced profile. This is used when a backbone element is being profiled, rather than an established type.
NameFlagsCardTypeDescription & Constraints
Extension
0..1Specific element for profile (for backbone elements)
 
extension
?..0
 
url
?..?
 
value[x] *
1..?
 
 
valueString *
1..?string