This is the only place in the SDL source identifying this controller as a SwitchInputOnlyController
$ grep 0xa718 src/joystick/controller_list.h
{ MAKE_CONTROLLER_ID( 0x20d6, 0xa718 ), k_eControllerType_SwitchInputOnlyController, NULL }, // PowerA Nintendo Switch Nano Wired Controller
The SDL source has a testcontroller.c you could compile and run.
You can also check whether there is an entry in the GameControlerDB. Probably not, because it’s a standard Switch mapping?