How can I determine whether the plugin has been used?

Hi @burtonlo,

you can use this code snippet to display the table with all custom permalinks set with my plugin that differ from the native permalinks:

function pm_debug_pm_urls() {
	if(isset($_GET['debug_urls'])) {
		global $permalink_manager, $permalink_manager_uris;

		if(!empty($permalink_manager_uris)) {
			$uri_post_class = $permalink_manager->functions['uri-functions-post'];
			$home_url = Permalink_Manager_Helper_Functions::get_permalink_base();

			remove_filter( '_get_page_link', array($uri_post_class, 'custom_post_permalinks'), 99, 2);
			remove_filter( 'page_link', array($uri_post_class, 'custom_post_permalinks'), 99, 2);
			remove_filter( 'post_link', array($uri_post_class, 'custom_post_permalinks'), 99, 2);
			remove_filter( 'post_type_link', array($uri_post_class, 'custom_post_permalinks'), 99, 2);
			remove_filter( 'attachment_link', array($uri_post_class, 'custom_post_permalinks'), 99, 2);

			$html = "<table border=\"1\">";
			$html .= sprintf("<thead><tr><th>%s</th><th>%s</th></tr></thead>", 'Original URL', 'Permalink Manager URL');
			foreach($permalink_manager_uris as $id => $uri) {
				if(!is_numeric($id)) { continue; }

				$original_permalink = user_trailingslashit(get_permalink($id));
				$custom_permalink = user_trailingslashit($home_url . "/" . $uri);

				if($original_permalink == $custom_permalink && $original_permalink !== '/') { continue; }

				$html .= sprintf("<tr><td>%s</td><td>%s</td></tr>", $original_permalink, $custom_permalink);
			}
		}

		echo $html;
		die();
	}
}
add_action('init', 'pm_debug_pm_urls');

Please paste it to functions.php file in your (child) theme directory and then trigger by adding ?debug_urls=1 parameter to any URL, eg.:
https://yourwebsite.com/?debug_urls=1

Best regards,
Maciej

Thank you!