User profiles don’t have anything to do with the OPC-UA server.
As far as access rights go - when exposing Ignition tags via the OPC-UA server, the tag’s configured access level is honored.
There are currently three namespaces used in the server:
0 - reserved for nodes defined by the OPC foundation.
1 - nodes belonging to the server, including the device folder and all nodes from devices.
2 - used by the “expose sqltags” functionality. nodes representing exposed tags belong to this namespace.
Namespaces are not extensible or accessible to module developers in any way. Aside from their influence on what a node’s NodeId will be they are not something that anybody needs to be concerned with.