Registers a custom theme directory as an alternative to the default WP theme directory.

register-theme-directory.inc.php

<?php
/**
 * Plugin Name:     EggMUP: Register Custom Theme Directory
 * Plugin URI:      https://gist.github.com/ianpegg/fedff025099e5db13e618c5bc6c0c597
 * Description:     Register an alternative theme directory.
 * Version:         1.0.0
 * Author:          Ian Pegg
 * Author URI:      https://eggcupwebdesign.com
 * php version 7.4.15
 *
 * @category Must_Use_Plugin
 * @package  WordPress_Plugin
 * @author   Ian Pegg <[email protected]>
 * @license  GNU/GPLv3 https://www.gnu.org/licenses/gpl-3.0.txt
 * @link     https://eggcupwebdesign.com
 */

namespace EggCup\MUP\CustomThemeDir;

if (!defined('ABSPATH')) {
    exit;
}

if (defined('WP_CONTENT_DIR')) {
    register_theme_directory(constant('WP_CONTENT_DIR') . '/skin');
}