ext_localconf.php

<?php

if (!defined('TYPO3_MODE')) {
	die('Access denied.');
}

/** @noinspection PhpUndefinedVariableInspection */

// plugin configurations
\TYPO3\CMS\Extbase\Utility\ExtensionUtility::configurePlugin(
	'SGalinski.dd_googlesitemap_plugin',
	'GoogleSitemap',
	array(
		'GoogleSitemap' => 'index',
	),
	array(
		'GoogleSitemap' => '',
	)
);

?>