http://hl7.org/fhir/StructureDefinition/valueset-expand-rules|5.2.0

Defines how concepts are processed into the expansion when it's for UI presentation.
NameFlagsCardTypeDescription & Constraints
Extension
0..1all-codes | ungrouped | groups-only
 
extension
?..0
 
url
?..?
 
value[x] *
1..? ExpansionProcessingRule (example)
 
 
valueCode *
1..?code ExpansionProcessingRule (example)