I have a Max X Hero Wifi and I do not recall, or see in the manual, anything called a Bios Programming header, or called something else but could be a Bios Programming header. Where is this header located?
I also have a Crosshair VIII Dark Hero (X570) that does have a Node header. There is a diagram of the header in the manual but it is just an orientation diagram showing a rectangular header with 2 rows of pins - 6 on the top row and 5 on the bottom (3rd pin from the left is omitted), and Pin 1 is the lower left pin. I assume the view is looking down at the header on the mobo. It does not identify what any of the other pins do.
Here is a picture of it. It's not enough info to solve what you are trying to do but its a start.