Just out of curiosity, I went looking for where this was used, and found it here.
#if !PICO_STDIO_USB_RESET_BOOTSEL_FIXED_ACTIVITY_LED
if (request->wValue & 0x100) {
gpio = request->wValue >> 9u;
}
active_low = request->wValue & 0x200;
#endif
To my non-expert eyes, it looks like the flag for active_low actually overlaps with the value being read out for gpio ?