User blog comment:ASDFGirl/The Future of Fossils and Archeology: Revival/@comment-98.26.156.175-20180820145503/@comment-209.188.131.198-20180820152455

Bug testing. The devs have their own build of the game that they play on. They refuse to share, ostensibly for testing reasons, but I think they just enjoy being the only one with the mod. ;)

-Raptorofwar

P.S. Joking.