It's a real chain all right. Their website is here: http://www.whataburger.com/. I eat there a lot in the wee hours of the morning, as they are open 24/7. And it's really good too.
We got one burger place also open 24/7
They are so so, called "TicoBurger"
But, if you wanna eat good, you have to get a burger with like 5 meat patties cause they are slim thin! LMAO