materio-base-d7/sites/all/modules/contrib/panels/panels/templates/panels-dashboard.tpl.php

<?php
?>
<div class="panels-dashboard clearfix">
  <div class="dashboard-left clearfix">
    <?php print $left; ?>
  </div>

  <div class="dashboard-right clearfix">
    <?php print $right; ?>
  </div>
</div>