The AmbientOcclusion field is a member of the SceneCameraDebugMode enumeration in the Sandbox API. It represents a debug mode for the scene camera that visualizes ambient occlusion effects. Ambient occlusion is a shading and rendering technique used to calculate how exposed each point in a scene is to ambient lighting, which helps to add depth and realism to the scene by simulating soft shadows.

To use the AmbientOcclusion debug mode, set the scene camera's debug mode to SceneCameraDebugMode.AmbientOcclusion. This will render the scene with ambient occlusion effects, allowing you to visualize and debug how ambient occlusion is applied in your scene.