icingaweb2/modules/monitoring/application/views/scripts/show/components/perfdata.phtml

<?php if (! $object->perfdata) return ?>
<tr class="newsection">
 <td colspan="2">
  <h2><?= $this->translate('Performance data') ?></h2>
 </td>
</tr>
<tr>
 <td colspan="2" class="performance-data">
  <?= $this->perfdata($object->perfdata) ?>
 </td>
</tr>