crop-monitor/core/model/modx/registry/db/metadata.mysql.php

<?php

$xpdo_meta_map = array (
  'xPDOSimpleObject' => 
  array (
    0 => 'modDbRegisterQueue',
    1 => 'modDbRegisterTopic',
  ),
  'xPDOObject' => 
  array (
    0 => 'modDbRegisterMessage',
  ),
);