What is the functionality of the internal datapoints _Ui, _ReduManager?

Datapointtypes resp. datapoints using underline "_" as first character in their names are internal datapointtypes resp. internal datapoints.
The "_Ui" is the internal datapointtype for the user interface. For each started User Inteface manager with a number X an internal datapoint with the name "_Ui_<X>" from the datapointytpe "_Ui" must exist. This _Ui internal datapoint Contains all information of panels, layers etc.
The "_ReduManager" datapointtype contains the internal datapoints _ReduManager and ReduManager2 with the information about the redundancy- and connection-state between the redu-server.
In the WinCC OA OnlineHelp, in chapter "Reference tables --> Internal datapoint types" a functionlity descriptions of the elements of these two and other internal datapointtypes is available.