qmk-dactyl-manuform-a/keyboards/spaceman/2_milk/keymaps/mouse/keymap.c

#include QMK_KEYBOARD_H

const uint16_t PROGMEM keymaps[][MATRIX_ROWS][MATRIX_COLS] = {
      [0] = LAYOUT(
          KC_BTN1,
          KC_BTN2	
          )
};