I originally thought this was an emulator to run (original) AT&T Unix applications on a PC. Then I googled it and found the article you linked. The photo in the article doesn't really give you a good idea of how the system looked like when in use, here's a better one: https://oldcomputers.net/pics/att-unix-pc-left.jpg . If the keyboard is attached to the main case, the design makes it look so flush that you can overlook the fact that it's detachable.
