Total uses an advanced function (wpex_get_page_subheading) located at Total/framework/page-header.php to output the subheading for any given post, page or archive. But don’t go editing this function if you want to alter the subheading because you will run into issues in the future and also when you update your theme you will lose your changes. There are better ways of tweaking your subheading.
Adding A Subheading Via The Meta Settings
The default way of adding your subheading for posts and pages is via the meta option, see the screenshot below:
Adding & Altering The Subheading Via The Theme Filter
But what happens on archives? Well the theme itself will output the subheading that best fits such as the category description. And of course archives don’t have meta options like posts/pages so you can’t “easily” customize it via the dashboard. Also if you want to alter the page setting for multiple posts/pages it becomes a pain in the rear to do so via the page settings. For this reason I added a theme filter so via a simple function in your child theme you can quickly/easily tweak your page subheading anywhere on the site and even add one in places where they may not be one to start with.