Color extra field

Color extra field

Good morning,
I'm creating the product data sheet by calling the extra fields of type color in the default.php file using this command:
  1. <? php
  2. // simply prepend the alias with "_ef_"
  3. if (! empty ($ this-> item -> _ ef_certificato)) {
  4. echo '<ul>';
  5. foreach ($ this-> item -> _ ef_certificato as $ key => $ file_input):
  6. echo '<li>'. $ file_input. '</li>';
  7. endforeach;
  8. echo '</ul>';
  9. }
  10. ?>
I would like to view only the file that has been uploaded in the extra field; analyzing the file administrator/components/com_djcatalog2/views/field/tmpl/fielddata.php, I saw that the field is recalled through the variable $file_input but in the frontend I still see the name of the field and not the value that interests me https://lavori.apiceweb.it/ronchiato/prodotti-ronchiato/pellet/pellet-ekofocus-abete.
What should I enter to make only the uploaded file appear?

Thanks so much
Matteo Fontana