J. Random Hacker

In computer slang, J. Random Hacker is an arbitrary programmer (hacker).
"J. Random Hacker" is a popular placeholder name in a number of books and articles in programming. J. Random Hacker even authored a book about ease of malicious hacking, "Adventures of a Wi-Fi Pirate". Also, "J. Random Hacker" was a main developer of I2P software.
Over time, J. Random X has become a popular cliché, a snowclone, in computer lore, with more types of "random" (meaning "arbitrary") categories of people, such as "J. Random Newbie", J. Random User, or J. Random Luser.