The VOIDRUNNER'S CODEX is LIVE! Explore new worlds, fight oppressive empires, fend off fearsome aliens, and wield deadly psionics with this comprehensive boxed set expansion for 5E and A5E!
Not sure if my adding to this is going to bump it up the message board, but I just saw the same ad today and I too am super curious about what this game was like! All I can find is that it was published by either "Sage Systems" or "Knights of Chivalry" (according to the wiki List of play-by-mail games)... though the advert says "Sanctuary Games" so who knows? I would assume that two of them are companies running the game, and one published and ran it?
Unfortunately that's all I could find. Googling any of those publishers doesn't show much of anything.