
Here's the summary: Maxis developed something called SimRefinery to simulate an oil refinery. It was never released to the public, and was thought to have been long lost or to have never even existed. But recently, an ex Chevron employee found a floppy disk containing the software.
Here's LGR talking about it and demonstrating it on real hardware: https://www.youtube.com/watch?v=DZ6Cqn5rTfs
Here's the game on Archive.org: https://archive.org/details/simrefinery
And here's a really in depth article about it: https://obscuritory.com/sim/when-simcity-got-serious/

I don't think this is nearly as worthwhile to play as the NES SimCity prototype that was found, being that SimRefinery was never meant to be a game and it also seems largely unfinished, but I still think it's awesome to get more of the Maxis history. SimCity was SO HUGE when it came out, it's easy to forget today how big it was back then, but stuff like this reminds us. And it's always awesome to see something that was thought to be long lost to be found just like that.