A.2.3 ATL_OpcAmlMetaModel library
The ATL_OpcAmlMetaModel library contains attributes that represent enumerations that come from the OPC UA metamodel and hence have no corresponding Node in the UA Namespace. The following enumeration-based attributes are provided:
AttributeId,
BuiltInType, and
ModellingRuleType.
Additionally, the ATL_OpcAmlMetaModel library contains the following AttributeTypes used to compose the specialized mapping of NodeId described in A.3.7:
NamespaceUri – An AttributeType with a data type of xs:anyURI to hold a NamespaceUri of a NodeId.
ExplicitNodeId – The primitive form of an absolute NodeId with the attributes shown in Figure A.1.

When an instance of ExplicitNodeId is used, only one of the four “Id” fields shall have a value, and the remaining three shall be deleted.
Alias – Represents an OPC UA Alias with the attributes shown in Figure A.2.

The ReferenceTypeFilter attribute is optional, and when omitted, the ReferenceType “AliasFor” shall be assumed. See the FindAlias Method in OPC 10000-17.