qmk_firmware/keyboards/yatara/drink_me/keymaps/dormouse/keymap.c

#include QMK_KEYBOARD_H

const uint16_t PROGMEM keymaps[][MATRIX_ROWS][MATRIX_COLS] = {
    [0] = LAYOUT(
        KC_SLEP,
        KC_MUTE,
        KC_VOLD,
        KC_VOLU
    )
};