I'm confused. What does "2" mean in the context of a web page? If the server broke wouldn't it cause a 500 HTTP response? This just seems odd: 'if error write "

I'm confused. What does "2" mean in the context of a web page? If the server broke wouldn't it cause a 500 HTTP response? This just seems odd: 'if error write "2"'. Maybe it is some kinda of secret society code: "I'm sorry Dave, I can not do that... TWO!!!!"