Inside the device is a OEM connector labeld J14 that probably served as development and debug access for components of the device.
Open your device according to this IFIXIT Guide:
The pads are coated with a solder mask. The solder mask can be removed carefully with a sharp object.
Be careful you don't want to cut any traces. This could damage and destroy your device! Pad size is 0.5mm
If you can identify some pins feel free to update this Schematic template
