What´s the PG rail on PSU?

[Bugs]

There is one grey wire on PSU´s - the PG rail or PWR_OK
Any1 can explain me the function of this wire?
Thanks.

[L337 M33P]

The PG rail is asserted to 5v when the PSU is operating within normal parameters. It is typically asserted 100-500ms after Power_On has been held low and the PSU has turned on.

In the case of overload or overheat or overvoltage, the PSU will de-assert PG and the voltage will drop to 0v on that line, or the PSU switches off.

The Motherboard responds to PG like so - When PG is asserted at turn-on, the Motherboard starts the POST and bootup routine. If PG is de-asserted when the computer is on then the motherboard will reset the system, or turn itself off.

[Bugs]

Thanks,
so the PSU controls the PG...
in case of overload PSU decrease PG to 0V and mobo responds to this by doing a shut down (if on Win) or just turn power off?