RoboMACs 2163 is the universe from which (one set of) the RoboMACs come from, the default setting of the original Usenet-posted version of the RoboMACs RPG by Dave Van Domelen. In the Usenetverse, it's considered a subset of alt.toys.transformers. It crossed over with the Classic LNH in Robot Invasion and the Superguy series Team M.E.C.H.A. during the Grand Tour.
In the year 1994, the first artificial intelligence came to life. In 2065, it struck, wiping out 90% of humanity from a shining city on the Moon. The second artificial intelligence struck back, creating the RoboMAC race. In 2163, MACE and the Guardians fight over the Earth, the Moon, and the fate of humankind!
More information is available on Dave Van Domelen's site over here. See also RoboMACs Exodus.