Usage
The Tracker is capable of tracking the location of any entity in the world, player or otherwise. This is especially useful, as it allows you to track other players and send them Thermonuclear War… care packages from afar. To start tracking an entity, simply Right-Click on it with the Tracker. This will expend 150.0 J.

Note the Tracker only keeps tabs on the X and Z coordinates of the entity along with what dimension they’re in, meaning there is still a little guesswork involved. If the entity dies or the player disconnects from the server, the Tracker will stop tracking them!