Easter eggs, fun little references or surprises hidden just below the surface, are practically a given for modern movies and video games. But they aren't the exclusive domain of entertainment media, and they go back farther than you might think. Programmers were hiding undocumented responses to software input commands as far back as the late 60s. Apparently someone at Microsoft was doing so in the 80s, too: A recently uncovered easter egg in the very first Windows release may have gone undiscovered for 36 years, complete with a surprise appearance by Valve chief Gabe Newell.

According to self-styled Windows archeologist Lucas Brooks, there's a short list of Windows development team members encrypted into a bitmap file in the original Windows 1.0 release. Subsequent updates of the OS would have allowed users to reveal the “Congrats! The Windows Team” credits with some complex keystrokes, but there doesn't appear to be any way to show it in version 1.00, either by design or error. It's possible that no one ever found the message in the original software before Brooks did.

The Easter egg is simply a list of thirty-six names without job descriptions. Tech historians will immediately recognize Steve Ballmer, Microsoft's CEO following Bill Gates' retirement. But there's another name that's perhaps even more famous today, as noted by PCGamer. Gabe Newell is in the list as well. Yes, it's that Gabe Newell. He joined Microsoft after dropping out of Harvard in 1980, going on to work as a producer on the first three versions of Windows.

Newell co-founded Valve in 1996, published Half-Life in 1998, and lead the production of the Steam PC gaming distribution platform in 2003. In a Code.org interview with students in 2017, Newell said that he “learned more in three months with those guys at Microsoft than I did the entire time I was at Harvard.”