And they call this a time-traveler T-shirt.

As in, a Time Traveler Essentials T-Shirt.

Yeah, right. It doesn’t mention once either black powder or alcohol.  Look: it’s great to bring up nuclear fission and everything, but those two inventions combined will fuel any number of gunpowder empires that one might care to foster.

Sheesh.  Maybe they thought that potential owners had already memorized the relevant bits anyway.