Not sure it lines up correctly, schematic to image, but is it connected to M_BIOS connector?
If yes, online I found:
"The M_BIOS connector allows you to update the BIOS firmware on your ASUS motherboard even if your system is unable to boot or if the current BIOS version is incompatible with the update process."
If that's what it is, would it even need to be connected at all if you weren't flashing the BIOS?