zmk_mf68/app/dts/behaviors/mod_tap.dtsi

/ {
	behaviors {
		mt: behavior_mod_tap {
			compatible = "zmk,behavior-hold-tap";
			label = "MOD_TAP";
			#binding-cells = <2>;
			flavor = "hold-preferred";
			tapping_term_ms = <200>;
			bindings = <&kp>, <&kp>;
		};
	};
};