|FHIR Infrastructure Work Group||Maturity Level : N/A||Standards Status : Informative|
Identifies a profile structure or implementation Guide that applies to the datatype this element refers to. If any profiles are specified, then the content must conform to at least one of them. The URL can be a local reference - to a contained StructureDefinition, or a reference to another StructureDefinition or Implementation Guide by a canonical URL. When an implementation guide is specified, the type SHALL conform to at least one profile defined in the implementation guide.
When the base type is an abstract type (e.g. Resource or Element) then this extension defines which concrete types are allowed to be used for a parameter. In the absence of this extension, any type is allowed.