zmk_mf68/app/boards/native_posix.overlay

#include <behaviors.dtsi>
#include <dt-bindings/zmk/keys.h>
#include <dt-bindings/zmk/kscan-mock.h>

/ {
	chosen {
		zmk,kscan = &kscan;
	};

	kscan: kscan {
		compatible = "zmk,kscan-mock";
		label = "KSCAN_MOCK";

		rows = <2>;
		columns = <2>;
		exit-after;
	};
};