// custom post state
add_filter('display_post_states', 'theme_slug_custom_post_states');
function theme_slug_custom_post_states($states) {
global $post;
if( ('page' == get_post_type($post->ID) ) && get_page_template_slug( $post->ID ) ) {
$templates = get_page_templates();
if( empty( $templates ) ){
return $states;
}
$template_slug = get_page_template_slug( $post->ID );
foreach ( $templates as $key => $value ) {
if ( $value == $template_slug ){
$states[] = "<small>" . $key . " template</small>";
}
}
}
return $states;
}