Ask HN: How do I figure out the JSON challenge?

Please help. I personally dont care about the job, this challenge is just bugging and I need help. Any hints or suggestion would be appreciated.

If you go to this site: https://www.rainforestqa.com/jobs/ And click apply it’s a Challenge...I don’t care about the job I just want to figure out the challenge loll it's been bugging me.

So far I believe it's some sort of JavaScript challenge which would then unlock into the application site.... This link might help understand also: http://www.jsontest.com/

Thank you