I'm looking into using a USB 3.1 type-A port (ref: 632121300001) and its male counterpart that comes with a "PD DETECT" pin. I'm looking to make a USB-A to USB-C cable. I might be missing something really obvious but I cannot find anything in the USB-C specs about this. Those only ever mention 8-core cable assemblies for USB-A to USB-C.
At first glance, I thought this might just be a PD DETECT <> CC line, but the more I look around and the less it looks like it. Now I'm wondering if it's exclusively used for E-markers for PD. This would still make it a CC-related pin but would make it meaningless to connect it to an actual CC line for pullup/pulldown resistors.
What is the PD DETECT pin used for and how does it connect to a USB-C connector (if at all?)?