The original documentation came from the USI WM-N-BM-09 (P0) datasheet, and that’s how the pads on the Photon are connected to the P0.
However, it was never implemented in the Broadcom/Cypress WICED software that runs on the P0, so the coexistence interface effectively can’t be used. At one point we hoped that they would implement it, but that does not appear to be the case so we should remove that section from the datasheet.