Linedef type 432, Enable/Disable 2D Mode, is a type of linedef executor which, when triggered by a player, switches that player into, or out of, 2D mode.
Setup
The tag given to this linedef is irrelevant. Normally the player will be switched into 2D mode. However, if Flag [6] / Not Climbable is checked, the player will be switched back into 3D mode again.
Linedef special info
Linedef flags
[6] Not Climbable: Switches player back into 3D mode