source/php/Parser/EventManagerApi.php
public function deleteEmptyTaxonomies()
    {
        if (!empty(get_object_taxonomies('event'))) {
            foreach (get_object_taxonomies('event') as $taxonomy) {
                // Skip Event Groups and categories
                if ($taxonomy == 'event_groups' || $taxonomy == 'event_categories') {
                    continue;
                }

                $terms = get_terms(
                    array(
                        'taxonomy' => $taxonomy,
                        'hide_empty' => false,
                        'childless' => true,
                    )
                );

                foreach ($terms as $term) {
                    if ($term->count == 0) {
                        wp_delete_term($term->term_id, $taxonomy);
                    }
                }
            }
        }
    }
public function deleteEmptyTaxonomies()
    {
        if (!empty(get_object_taxonomies('event'))) {
            foreach (get_object_taxonomies('event') as $taxonomy) {
                // Skip Event Groups and categories
                if ($taxonomy == 'event_groups' || $taxonomy == 'event_categories') {
                    continue;
                }

                $terms = get_terms(
                    array(
                        'taxonomy' => $taxonomy,
                        'hide_empty' => false,
                        'childless' => true,
                    )
                );

                foreach ($terms as $term) {
                    if ($term->count == 0) {
                        wp_delete_term($term->term_id, $taxonomy);
                    }
                }
            }
        }
    }
Delete empty event taxonomies
@return void