View file system/functions/hooks/reg_foot.php

<?php
  
function reg_foot() {
  
  ?>
  <br /><br />
  <center>
  <a style="background-color: #546E7A; line-height: 30px; padding: 7px 1em; color: white; border-radius: 4px" ajax="no" id="modal_bottom_open_set" onclick="upload('/system/AJAX/php/ulogin.php', 'attachments_upload')"><?=lg('Авторизация через соц.сети')?></a>
  </center>
  <?
    
}