What does mean $db->Escape($_GET['user'])

I bought some script they are about uploading files i found this $db->Escape($_GET['user']) what does mean and what does do $db->Escape i tried to create test.php with only

$db->Escape($_GET['user']); but didn't work

example.com/test.php?user=RandomusernameHere

How can find sorce of this code i had to attach a config to make it work it is like this

<?php include('admin-control/config.php'); $showthis = $db->Escape($_GET['user']); echo $showthis; ?>

in config dosn't seems clear are only language and error logs and why is working only with config.php