Question abour ESP_IO0 pin

[silelis]

Hello,
Till now I have used Jlink (jtag) to debug and flash ESP32. But I'm going to start with ESP32_Prog.
I have found ESP_PROG to ESP32 as on Yout git repo and have a question.
In my project GPIO0 is design do other purposes (interrupt request to other mcu) and I have got no GPIOs available to switch it.
So my question:
What is the purpose of ESP_IO0 during flashing/ debuging via ESP_PROG?
Can I connect GPIO0 both to:

• other mcu (so it will work during normal work)
• ant to ESP_Prog (so it will work during flashing - I assume that during flashing only because Jlink do not use this pin during debugging)?