wp_maintenance

	// Make sure the environment is an allowed one, and not accidentally set to an invalid value.
	if ( ! in_array( $current_env, $wp_environments, true ) ) {
		$current_env = 'production';
	}

	return $current_env;
}

/**
 * Don't load all of WordPress when handling a favicon.ico request.
 *
 * Instead, send the headers for a zero-length favicon and bail.
 *
 * @since 3.0.0
 * @deprecated 5.4.0 Deprecated in favor of do_favicon().
 */
function wp_favicon_request() {
	if ( '/favicon.ico' === $_SERVER['REQUEST_URI'] ) {
		header( 'Content-Type: image/vnd.microsoft.icon' );
		exit;
	}
}

/**
 * Die with a maintenance message when conditions are met.
 *
 * The default message can be replaced by using a drop-in (maintenance.php in
 * the wp-content directory).
 *
 * @since 3.0.0
 * @access private
 */
function wp_maintenance() {
	// Return if maintenance mode is disabled.
	if ( ! wp_is_maintenance_mode() ) {
		return;
	}

	if ( file_exists( WP_CONTENT_DIR . '/maintenance.php' ) ) {
		require_once WP_CONTENT_DIR . '/maintenance.php';
		die();
	}

	require_once ABSPATH . WPINC . '/functions.php';
	wp_load_translations_early();