Upload Using Programmmer

Upload_ISP.png

It may be interesting that a warning about this option is shown when the user is doing something related, perhaps a savings when the person compiles the ArduinoISP outline or when Arduino as the ISP programmer is selected.

You may need a mini tutorial for the first time it opens.

The Help that comes with the IDE does not appear to show this option

(file:/arduino-1.8.12/reference/www.arduino.cc/en/Guide/Windows.html#toc9)