"template called" does not mention the page template

I don't know if this is a code problem, UI problem, or if I misunderstand what the module is supposed to do. The output indicates the template called is modules/system/html.tpl.php. While it's true that that template is called, there is also a page template being called and the UI does not indicate this.

My theme's template.php file has some code to add the page's path alias to the theme_hook_suggestions array. So, I can visit the www.mysite.com/about page and the page--about.tpl.php template is called. I can confirm this is working by adding some text to that page--about.tpl.php template. However, the output from the devel_themer module makes no mention of this template.