WOTR Keys ID Prior and Next

What are the Keys Prior and Next in the Below?
Are they Right or Left Keys which are also already being used?

<Key ID="Prior" Mod="Shift" Action="HeadPitchUpRight" FriendlyDesc="Pitch Eyepoint Up Right" Category="ViewControl" P4Use="y"/>
<Key ID="Next" Action="RUDDER_RIGHT" FriendlyDesc="Rudder Right" Category="AircraftControl" P4Use="y"/>
<Key ID="Next" Mod="Control" Action="RUDDER_TRIM_RIGHT" FriendlyDesc="Rudder Trim Right" Category="AircraftControl" P4Use="y"/>
<Key ID="Next" Mod="Shift" Action="HeadPitchDownRight" FriendlyDesc="Pitch Eyepoint Down Right" Category="ViewControl" P4Use="y"/>

<Key ID="Right" Action="AILERONS_RIGHT" FriendlyDesc="Ailerons Right" Category="AircraftControl" P4Use="y"/>
<Key ID="Right" Mod="Control" Action="AILERON_TRIM_RIGHT" FriendlyDesc="Aileron Trim Right" Category="AircraftControl" P4Use="y"/>
<Key ID="Right" Mod="Shift" Action="HeadRotRight" FriendlyDesc="Rotate Eyepoint Right" Category="ViewControl" P4Use="y"/>
<Key ID="Left" Action="AILERONS_LEFT" FriendlyDesc="Ailerons Left" Category="AircraftControl" P4Use="y"/>
<Key ID="Left" Mod="Shift" Action="HeadRotLeft" FriendlyDesc="Rotate Eyepoint Left" Category="ViewControl" P4Use="y"/>
<Key ID="Left" Mod="Control" Action="AILERON_TRIM_LEFT" FriendlyDesc="Aileron Trim Left" Category="AircraftControl" P4Use="y"/>

PGUP PGDN if memory serves,,

Thank you.