The codebase here is so much cleaner and better organized than the version I remember wrestling with on a daily basis, and if you remember how buggy and unstable the DayZ launch was for users it can all be traced back to this since it was never envisioned to live as long and scale as far as it did. Fun fact Poseidon was the original internal game name they were building in 1999 before changing the game name and renaming the engine to Real Virtuality.
It's also easy to forget just how far ahead of its time this was since this shipped large open worlds with maps that were 12.5 km × 12.5 km and that was really easy to mod with a runtime scripting language SQF, not a separate mission editor. This was all in 2001, which is three years before Half-Life 2 would come out.