qmk-firmware/keyboards/spaceman/2_milk/keymaps/via/keymap.c

#include QMK_KEYBOARD_H

const uint16_t PROGMEM keymaps[][MATRIX_ROWS][MATRIX_COLS] = {
      [0] = LAYOUT(
          KC_Z,
          KC_X
      ),
      [1] = LAYOUT(
          _______,
          _______
      ),
      [2] = LAYOUT(
          _______,
          _______
      ),
      [3] = LAYOUT(
          _______,
          _______
      )
};