Server Response Header "Cowboy"

Bonus answer "etymology": It doesn't say on it's GitHub page (https://github.com/heroku/cowboy), but here are some guesses:

• Because it runs on Ranch (https://github.com/heroku/ranch): Ranch is a socket acceptor pool for TCP protocols?
• Possibly also because it sees Apache as a competitor?

That would probably be heroku/cowboy. "Cowboy" is just an arbitrary project name that ninenines/cowboy chose. It's just as random as "Apache" (a patchy version of its predecessor), "nginx", "unicorn", etc.