Newbie question

I have noticed 3 two letter php files in my root today.

ut.php, it.php, dl.php

This is usually a really bad sign but in this case I found out that they all belong to phplist’s core files.

A casual glance into the code didn’t tell me what the exact purpose of those files could be.

A (to be honest lazy) Google search also didn’t shed any light.

If you are familiar with the purpose of those files, please shed some light.

Kind regards,