The circuit in question could also be enabled or disabled by using a high-energy laser pulse to blow out a tiny fuse on the ICs as they sit on the wafer, before

The circuit in question could also be enabled or disabled by using a high-energy laser pulse to blow out a tiny fuse on the ICs as they sit on the wafer, before sending the wafer out to be cut into individual ICs which are then subsequently packaged into the seemingly ordinary chips that we are all familiar with.