Unfortunately only the error codes are listed in the literature. If anyone finds out for sure I'd like to know, but my strong suspicion is that they are software and hardware revision numbers. I work in electronics and have more electronics test equipment than welders and every piece does that as well as all of my employers products, that is those that contain microcontrollers. When I saw the startup codes for the first time I thought "they do it too".
Harris dual-stage O/A
Lincoln AC/DC buzzbox
Miller 3035 spoolgun
Thermal Arc 185
Thermadyne Cutmaster 52
Angle grinders, vicegrips, the usual suspects
Two hands, tired body, not enough time...