On The front we can spot

Bluetooth antenna (on the board)

Battery connectors

Murata 2x2mm RF switch connector, that can be used for RF testing

U11, U13 - probably some chips behind the shield, which is (unfortunately) firmly soldered. My guess: one of them is ultra-low power microcontroller and the other one is taking care of power delivery to the board

J1 - place for debug connector (empty in production)