The keyboard has a special firmware that lives on, and operates separately of, the operating system. In a nutshell, it detects if
F1, F2 and F3 keys are pressed for 10s. Once one of the keys get pressed for the set duration, the keyboard firmware cuts power to the chosen aforementioned peripheral. The implementation is no different to cutting a peripheral power mechanically via a physical switch, and the power state settings for each is stored across reboots.
This is privacy switch implementation is highly secure since the firmware that dictates if peripherals get powered is not a part of the Pinebook Pro’s operating system. The power state value for each peripheral also cannot be overridden from the operating system. In fact, the keyboard firmware itself cannot be accessed from the operating system.