Unlike the GBC and GBP, this board allow you charge the battery and take out the audio with a USB-C earphone (or use them with a USB-C to jack audio adapter)!
However, this board it's extremely small and you will need to solder 6 small pads. So, it can be a bit difficult. It will not support usb-c to usb-c cables.
This kit includes:
1 board.
1 plastic cap to cover the hole (3D Printed bezel).
Installation instructions can be found here.