qmk_firmware/layouts/community/ortho_1x1/test/keymap.c

#include QMK_KEYBOARD_H

const uint16_t PROGMEM keymaps[][MATRIX_ROWS][MATRIX_COLS] = {
    /*
     * ┌───┐
     * │ A │
     * └───┘
     */
    [0] = LAYOUT_ortho_1x1(
        KC_A
    )
};