"In the teardown you can see there is only one board." I'm curious - can one buy that one board ? It is an odd form-factor that I have not seen a raspi use in

"In the teardown you can see there is only one board." I'm curious - can one buy that one board ? It is an odd form-factor that I have not seen a raspi use in the past (long and rectangular) - is it only sold as part of these keyboard units ?