static protected function getPostsIdsToExport() {

		$post_ids_to_export = [];

		global $wpdb;
		$results = $wpdb->get_results(
			$wpdb->prepare(
				"SELECT ID FROM {$wpdb->posts} WHERE post_status IN (%s, %s) AND post_type IN (%s, %s, %s, %s, %s)",
				[ 'private', 'publish', 'front-matter', 'part', 'chapter', 'back-matter', 'glossary' ]
			), ARRAY_A
		);
		foreach ( $results as $val ) {
			$post_ids_to_export[ $val['ID'] ] = 'on';
		}

		return $post_ids_to_export;
	}