Collection.php

<?php
/**
 * Copyright © Magento, Inc. All rights reserved.
 * See COPYING.txt for license details.
 */
namespace Magento\Theme\Model\Theme;

/**
 * Theme filesystem collection
 *
 * @deprecated 100.2.0 There is no need for the class provided themes list to be in Theme module
 */
class Collection extends \Magento\Framework\View\Design\Theme\ThemeList
{
    //
}