In FLC there is a need to represent node identification information (NodeId, browse path) of nodes in another server in structures.
We had such requirements before, especially in product implementations.

It is not possible to use the DataTypes NodeId and QualifiedName since the namespace index is the index of the local server and it is not possible to add all namespaces of all referenced servers to the namespace table of the server that holds the information. But this is also not possible since referenced servers will use identical namespace URIs with different instance nodes.

For NodeId we have the ExpandedNodeId but this contains a server index and the use would require that all servers are in the server list.

We need DataTypes for NodeId and QualifiedName that contain a namespace URI instead of a namespace index.