A camera feed gives you access to a single physical camera attached to your device. When enabled, Godot will start capturing frames from the camera which can then be used. See also [CameraServer].
[b]Note:[/b] Many cameras will return YCbCr images which are split into two textures and need to be combined in a shader. Godot does this automatically for you if you set the environment to show the camera image in the background.