It is an op amp used as voltage follower to make a dual supply from a single one. It is capable of large current thanks to the two power transistors configured in push-pull. It is also immune to noise. Try to change the two resistor value and see that the voltage still to be fixed at 12v ( a virtual ground ). The switch is needed to avoid the "can't solve" problem at the start of simulation so remind to open it before saving.
