Find out how to get menu strings, classes and tags into po file for translation

I am prepping my theme for translation. I’ve added the next line to my features.php, and added the textual content area inside my theme information.

<?php /*** LOAD THEME TEXTDOMAIN ***/
load_theme_textdomain( 'mytheme', get_template_directory() . '/languages' );

$locale = get_locale();
$locale_file = get_template_directory() . "/languages/$locale.php";

if ( is_readable( $locale_file ) ) {
    require_once( $locale_file );
}

?>

I’ve used poedit to generate my po information. It’s discovering a number of the strings which might be labeled with the textual content area, but it surely’s not discovering my menu objects, classes, or tags. Guessing I am lacking one thing?

I did some digging and I could not discover any solutions. Finally that is for a front-end translation – wp admin will stay in english.

BTW, the menu relies on wp-bootstrap-navwalker