OptionalapplicationApplicationUri from the Client certificate, if any.
OptionalclientTrue when the Client certificate was admitted only by a relaxation (not trusted).
OptionalendpointEndpoint URL used by the Session, if known.
OptionalsecuritySecureChannel security mode.
OptionalsecuritySecureChannel security policy URI.
Session attributes a resolver may use to evaluate application/endpoint restrictions on a Role (OPC 10000-18 §4.4.1).