coll.php

<?php include 'plugins.php';?>
<p>
  <button class="btn btn-danger" type="button" data-toggle="collapse" data-target="#collapseExample" aria-expanded="false" aria-controls="collapseExample">
    Button with data-target
  </button>
</p>
<div class="collapse" id="collapseExample">
  <div class="card card-body">
    Anim pariatur cliche reprehenderit, enim eiusmod high life accusamus terry richardson ad squid. Nihil anim keffiyeh helvetica, craft beer labore wes anderson cred nesciunt sapiente ea proident.
  </div>
</div>