The Xbox was Microsoft's first entry into the game console market, releasing in 2001.
While easter eggs in the console itself were discovered, it took this one nearly 20 years to be revealed by one of the developers. When copying the soundtrack from a CD, set the title to "Timmyyyyyyyyyyyyyyyyyyyyyyyyyy!" (26 y's) and let it finish ripping the soundtrack. Then go back into Settings, and into System Info. The page will then display some developer credits.