Automatically changes the camera angle based on terrain. If the character climbs a slope, the camera will rotate upwards; if the character descends it will rotate downwards. Only works if a smart following style is enabled.
Changing this setting
In-game, type the following
/console cameraTerrainTilt setting
Alternatively, you can exit wow, open the Config-cache.wtf file, and add the following line:
SET cameraTerrainTilt "setting"