URBEST 8mm Detecting Distance Approach Sensor Inductive Proximity Switch NPN NO DC 6-36V Cylinder Type

Is this sensor supposed to output voltage when not activated by metal? And if so, would that mean it is actually normally closed?

Does this sensor turn on when it touches metal or turns off?

what are those white power plugs for the Blue Brown and Black power called?

Do you need an optocoupler or resistors on an Anet A8 stock board? Or will it work if its plugged straight into the board?