Which twig file is being used and how?
You could use this variable to get the template name: {{ _self.getTemplateName() }}

Put it at the top of all your template files: 

&lt;!-- {{ _self.getTemplateName() }} --&gt;

And then for every template called it should have the commented out template name.

In Craft 3, there's a nice plugin called "Template Comments" which is great for this... But I don't see a version for Craft 2.