Display Categories in firesale

Question

I am using firesale categories to display all the categories. Here is my code...

{{ firesale:categories}}
        {{ entries}}
           <p><a href="{{ firesale:url route='category' id=id }}">{{ title }}</a></p>
        {{ /entries}}    
  {{ /firesale:categories }}

It displays categories just as expected. But I am trying to view the array structure of the categories. (to get id, parent, slug etc from the individual categories).. I have tried the following code but it does not work.

  {{ firesale:categories}}
       <?php 
            echo "<pre>";
            print_r($entries);
        ?>
    {{ /firesale:categories }}

How can I view the array structure of the categories?