Boss Checklist - Eternal Battletowers Compatibility

This is an addon mod for both Eternal Battletowers and Boss Checklist that integrates the former's Tower Guardian bosses into the latter's boss checklist interface as an entry.

"How did you make this work? Eternal Battletowers is a data pack bundled as a mod!"
To begin with, the mod adds a fake, unspawnable stand-in entity that acts as the foundation for the boss checklist entry you see. The boss's entry is automatically marked as defeated once a player is detected to have earned the advancement attributed to defeating the Tower Guardian.

"Why isn't this bundled with your other Boss Checklist addons?"
This mod uses an aforementioned fake entity that is added by this mod itself. Thus, the Tower Guardian boss entry will appear regardless of whether or not you actually have the Keebsz's Battle Towers mod installed. You wouldn't want a modpack where players would go around curiously searching for this "Tower Guardian" only to figure out later down the line that they do not even have the mod supposedly accommodating the boss installed in the first place.