In Terry Pratchett’s novel Going Postal, an allegory about the creation of an Internet-like telegraph system called “the clacks,” workers who die in the line of duty have their names “sent home,” by being transmitted up and down the line in the system’s signalling layer (“A man is not dead while his name is still spoken”).
GNU Terry Pratchett, which works with both Apache and Nginx, causes web-servers to transmit a special “X-Clacks-Overhead” header, reading, “GNU Terry Pratchett,” so that Terry’s name lives on in the Internet’s “overhead” forever.
(via Hacker News)