The XR Battery (B2XR) is a 13S2P battery pack, with LG INR18650HG2 cells.
The main micrcontroller is a Microchip dsPIC33EP512GP504, and has an ISSI IS25LP128 128Mbit/16Mbyte flash chip connected via SPI.
Battery balancing and monitoring is handled by a TI BQ76940, with a TI BQ76200 acting as the main pack MOSFET monitor/controller.
The charging input and board output are both switched by the MCU, and default to being open -- unlike the V1 boards, you can't charge a V2 XR pack if it's dead by spinning the motors to backfeed the battery.
The top side of the BMS board is covered in a non-laquer based conformal coating, with a moat to prevent it from covering test pads or the main board connections. You can peel/chip it away with a bit of effort.
Opening the XR battery involves a lot of pyring and unpleasant popping noises as the glue gives way. I used car trim panel opening tools for most of the prying/case seperating, and then resorted to a flat head screwdriver to give it the final nudge to be able to pull the pack from the housing. This YouTube video was my reference for opening the pack, albeit with less prying with a metal screwdriver.