Find out what template file a page is using

show_current_template.php

function show_current_template($wp_admin_bar) {
	global $template;
	$args = array(
		'id'    => 'current_template',
		'title' => 'Current Template: '.basename($template),
		'meta'  => array('title'=>$template)
	);
	$wp_admin_bar->add_node($args);
}
if (current_user_can('manage_options') && !is_admin()) { add_action('admin_bar_menu', 'show_current_template', 9999); }