The original design of the TV-B-Gone by Adafruit uses the pin 6 of ATtiny85v as region detection. With a 10k pull-down resistor connected to the pin 6, the device generates codes for European TV models. Otherwise, floating the pin 6, it works for North American models and most Asian models as well.
There are three circuits showing in this step: North American (US) models only, European (EU) models only, and all-in-one model with region selection switch. The PCB I made and showed in the Intro section is the all-in-one model.
As you can see in the circuit diagram, the NA (or US) model has no pull-down resistor on the pin 6. When you successfully turn on or off a TV in the middle of code generation (the visible LED blinking), simply pushing the button S2 will pull the pin 6 to the ground and the firmware will stop the process and go to sleep mode which doesn't consume the battery.
However, in EU model, the pin 6 is grounded by the pull-down resistor, R3, 10k, always. But pulling up the pin 6 by pressing the button S2 and connect to Vcc, the modified firmware will stop the process and sleep. The UNI (all-in-one, NA+EU) model simply has both in one by adding a slide switch.