WordPress-Plugin-Boilerplate/plugin-name/trunk/uninstall.php

<?php
/**
 * TODO: Short description (no period for file headers)
 *
 * TODO: Long description.
 *
 * @package   Plugin_Name
 * @author    Your Name <email@example.com>
 * @license   GPL-2.0+
 * @link      http://example.com
 * @copyright 2014 Your Name or Company Name
 */

// If uninstall not called from WordPress, then exit.
if ( ! defined( 'WP_UNINSTALL_PLUGIN' ) ) {
	exit;
}