I found many identifiers in the generated files opcua_identifiers.h and Opc.Ua.Constants.cs where there is no related node in the nodeset.
I found them on Alarm ObjectTypes but I am not sure if other ObjectTypes are affected as well.

Most of them make no sense at all.
An extrem example are argument properties for ConditionRefresh/ConditionRefresh2 repeated on every alarm type.
#define OpcUaId_LimitAlarmType_ConditionRefresh_InputArguments 6127
#define OpcUaId_LimitAlarmType_ConditionRefresh2_InputArguments 12987

Just the ExclusiveLevelAlarmType has not a single child variale in the nodeset but 34 identifiers for children generated:
#define OpcUaId_ExclusiveLevelAlarmType_EnabledState_Id 9496
#define OpcUaId_ExclusiveLevelAlarmType_Quality_SourceTimestamp 9505
#define OpcUaId_ExclusiveLevelAlarmType_LastSeverity_SourceTimestamp 9507
#define OpcUaId_ExclusiveLevelAlarmType_Comment_SourceTimestamp 9509
#define OpcUaId_ExclusiveLevelAlarmType_AddComment_InputArguments 9514
#define OpcUaId_ExclusiveLevelAlarmType_ConditionRefresh_InputArguments 9516
#define OpcUaId_ExclusiveLevelAlarmType_ConditionRefresh2_InputArguments 12995
#define OpcUaId_ExclusiveLevelAlarmType_AckedState_Id 9518
#define OpcUaId_ExclusiveLevelAlarmType_ConfirmedState_Id 9527
#define OpcUaId_ExclusiveLevelAlarmType_Acknowledge_InputArguments 9536
#define OpcUaId_ExclusiveLevelAlarmType_Confirm_InputArguments 9538
#define OpcUaId_ExclusiveLevelAlarmType_ActiveState_Id 9540
#define OpcUaId_ExclusiveLevelAlarmType_SuppressedState_Id 9549
#define OpcUaId_ExclusiveLevelAlarmType_OutOfServiceState_Id 16699
#define OpcUaId_ExclusiveLevelAlarmType_ShelvingState_CurrentState 9558
#define OpcUaId_ExclusiveLevelAlarmType_ShelvingState_CurrentState_Id 9559
#define OpcUaId_ExclusiveLevelAlarmType_ShelvingState_LastTransition_Id 9564
#define OpcUaId_ExclusiveLevelAlarmType_ShelvingState_UnshelveTime 9568
#define OpcUaId_ExclusiveLevelAlarmType_ShelvingState_TimedShelve_InputArguments 9593
#define OpcUaId_ExclusiveLevelAlarmType_ShelvingState_TimedShelve2_InputArguments 24827
#define OpcUaId_ExclusiveLevelAlarmType_ShelvingState_Unshelve2_InputArguments 24829
#define OpcUaId_ExclusiveLevelAlarmType_ShelvingState_OneShotShelve2_InputArguments 24831
#define OpcUaId_ExclusiveLevelAlarmType_SilenceState_Id 16708
#define OpcUaId_ExclusiveLevelAlarmType_LatchedState_Id 18258
#define OpcUaId_ExclusiveLevelAlarmType_Suppress2_InputArguments 24379
#define OpcUaId_ExclusiveLevelAlarmType_Unsuppress2_InputArguments 24381
#define OpcUaId_ExclusiveLevelAlarmType_RemoveFromService2_InputArguments 24383
#define OpcUaId_ExclusiveLevelAlarmType_PlaceInService2_InputArguments 24385
#define OpcUaId_ExclusiveLevelAlarmType_Reset2_InputArguments 24387
#define OpcUaId_ExclusiveLevelAlarmType_GetGroupMemberships_OutputArguments 25163
#define OpcUaId_ExclusiveLevelAlarmType_LimitState_CurrentState 9597
#define OpcUaId_ExclusiveLevelAlarmType_LimitState_CurrentState_Id 9598
#define OpcUaId_ExclusiveLevelAlarmType_LimitState_LastTransition_Id 9603