Huh, TIL. I always assumed that they meant that the errors themselves are unicorns because they rarely happen and even when they do, you usually don't see them.

Ha, thanks :)

First time I saw that logo was on this Android ROM, I wonder which used it first?

http://aokp.co/

(they're using a different but similar image now, but they used to use that exact same logo)

That's a python server - based on the ruby server "Unicorn"