How to use Arduino nano 33 iot AREF pin for GPIO

I want to use the AREF pin of Arduino nano 33 IoT as GPIO.

The document says that the AREF pin can be used as a GPIO, but how can I refer to it?
Looking at the schematic, on the Arduino nano 33 iot, the AREF pin is connected to the PA03 port.
It cannot be compiled with pinMode (AREF, INPUT).

It was not mapped to an Arduino pin number in the Arduino boards platform (Arduino pin number is the index of this array):

This means you can't control this pin using the standard Arduino IO functions like pinMode. You can work with it at register level. Or you can use a modified core variant that maps it to an Arduino pin.

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Thank you very much.
I understand that it cannot be used with the standard Arduino description.

For compatibility with other nanoboards, I will not use it as a GPIO.