"Enterprise" systems usually refer to the in-house custom apps that businesses write for their own use and don't sell to anyone, e.g. "that thing Bob wrote that lets the merchants check how many foozits were purchased but not shipped yet". As anyone who has worked on such systems knows, these are almost uniformly the worst code imaginable. Most of them don't scale, have no tests, and are held together with chewing gum. It is possible that things are just as bad in the non-weaponry side of military coding, but I hope not.