Extension ele-1: All FHIR elements must have a @value or children
ext-1: Must have either extensions or value[x], not both
url 
value[x] ele-1: All FHIR elements must have a @value or children
XXXXThis is the set of resources that conform to either of the profiles FR Core Observation Level Of Exertion Extension (https://hl7.fr/ig/fhir/core/StructureDefinition/fr-core-observation-level-of-exertion) and FR Core Observation Level Of Exertion Extension (https://hl7.fr/ig/fhir/core/StructureDefinition/fr-core-observation-level-of-exertion). E.g. what you have to deal with if you get resources conforming to one of them
| XXXX | XXXX | XXXX | XXXX | XXXX |
|---|---|---|---|---|
| Extension | 0..* | FR Core Observation Level Of Exertion Extension ele-1: All FHIR elements must have a @value or children ext-1: Must have either extensions or value[x], not both | ||
| url | 1..1 | uri | identifies the meaning of the extension | |
| value[x] | 0..1 | CodeableConcept | Value of extension ele-1: All FHIR elements must have a @value or children | |
| XXXX | ||||