A bit off-topic, but I had the same thought when I read about Jenkins servers on the public Internet in this piece.[0]
But when I read that he had found a public facing Jenkins server owned by Google, I figured I must be missing something.
I run a 2 man shop, but I still keep things like Jenkins behind OpenVPN. Why would anyone leave Jenkins open? There must be a reason, right?
https://emtunc.org/blog/01/2018/research-misconfigured-jenki... [0]