http://hl7.org/fhir/StructureDefinition/obligation|5.2.0

When appearing on an element, documents obligations that apply to applications implementing that element. When appearing at the root of a StructureDefinition, indicates obligations that apply to all listed elements within the extension. When appearing on a type, indicates obligations that apply to the use of that specific type. The obligations relate to application behaviour, not the content of the element itself in the resource instances that contain this element. See the [Obligation](obligations.html) page in the core specification for further detail.