Acer BOARD.USB 55.HQFN7.001 is a notebook sub-board identified as a USB board. It is listed for Acer Chromebook 712 C871 and C871T models, making it a model-specific part for notebook service or repair.
The exact part number ties this board to the listed models and distinguishes it from other notebook sub-boards. Its documented role is as a USB board; the available product information does not specify port count, connector layout or package contents.