What does find() return in \DB\SQL\MAPPER class of fatfree?

Question

I came across this piece of code written by previous developers and I am confused by result of this find() method. It is all gibberish. What does it actually return when no arguments are passed to it?

$designation = new DesignationsModel();
$designations = $designation->find();

DesignationModel Class is as follows:

class DesignationsModel extends \DB\SQL\Mapper {

private $f3;
private static $instance;
protected $_name = 'designations';

 // Instantiate mapper
function __construct() {
    $db = \Base::instance()->get('DB');
    $this->f3 = \Base::instance();
    // This is where the mapper and DB structure synchronization occurs
    parent::__construct($db, $this->_name);
}

The result of $designations is used in View as:

<select name="designation_id" class="form-control" id="designations">
   <option></option>
     <?php

     foreach ($designations as $designation):
        if (isset($edit)):
          if ($designation->id === $users->designation_id) :
  ?>
  <option value="<?php echo $designation->id; ?>" selected><?php echo $designation->title; ?></option>
  <?php
          endif;
        endif;
  ?>
  <option value="<?php echo $designation->id; ?>"><?php echo $designation->title; ?></option>
  <?php endforeach; ?>
  </select>