Found this while scouring this list of HTTP status codes, because I wanted to make sure I was giving appropriate responses in this web API I'm developing.
Started off as an April's fools joke, people liked it enough to keep it in.
> “It's a reminder that the underlying processes of computers are still made by humans”
Nope, it's still funny, we're keeping it.
This makes it similar to 405 Method Not Allowed, 406 Not Acceptable, or 426 Upgrade Required.
> the server cannot or will not process the request due to something that is perceived to be a client error (for example, malformed request syntax, invalid request message framing, or deceptive request routing).