The CheckIfDead class could be useful to lots of open source developers, but in order for that to happen, it needs to be broken out into a separate repo and then included in the IABot repo via Composer or a similar mechanism.
In the process, we should probably break the checkDeadlinks() function into smaller testable pieces and add a convenience function for testing individual URLs (that is called something like 'isDeadLink' rather than 'checkDeadLink', which is ambiguous).
Finally, a README needs to be written with some basic documentation.
Existing code is here: https://github.com/cyberpower678/Cyberbot_II/blob/master/IABot/checkIfDead.php
Also, make this a composer package. This task does not include refactoring Cyberbot code to use the new library.