When we made the change to only CURIEs and absolute IRIs (in key, keyref, iri, type, style, material, ...), not allowing relative IRI references in these attributes, I forgot to modify the occurrence of xml:base attributes in the schema. It is no longer needed in any element except Data, where it can only be used to resolve relative IRI references given with xsi:type="xsd:anyURI".
Since xml:base is no longer needed to resolve the relative IRI references of any attribute values, it's use can be restricted to the Data element. It is actually only needed when the datatype is explicitly declared to be xs:anyURI (otherwise what might look like a relative IRI references is actually just a string). Further, it cannot be used together with the simple type declaration (xsi:type="xs:anyURI") because this type does not allow attributes. Therefore the minimal usage example looks like:
When we made the change to only CURIEs and absolute IRIs (in key, keyref, iri, type, style, material, ...), not allowing relative IRI references in these attributes, I forgot to modify the occurrence of xml:base attributes in the schema. It is no longer needed in any element except Data, where it can only be used to resolve relative IRI references given with xsi:type="xsd:anyURI".
Since xml:base is no longer needed to resolve the relative IRI references of any attribute values, it's use can be restricted to the Data element. It is actually only needed when the datatype is explicitly declared to be xs:anyURI (otherwise what might look like a relative IRI references is actually just a string). Further, it cannot be used together with the simple type declaration (xsi:type="xs:anyURI") because this type does not allow attributes. Therefore the minimal usage example looks like: