How does 3 USB_EN works?

From the Datasheet we could see that there are 3 USB_EN pin.
Could you explain how these works
such as:
They are high enable or low enable?
Is there any test method to test whether they works correctly or not?

There have USB0_EN_OC and USB1_EN_OC, they are open drain - 3.3V with 100kohm PU on module.
USB2_EN_OC is RSVD pin mean not connection on module, so can’t be used.
Plasea found detailed description from OEM DG, thanks.