Implicit variables/objects available in pre-request and tests script code

Just started using the Postman app editor to write my pre-request Script and tests code, I am puzzled to what implicit (built in) ‘context’ variables I may acces in js code. For example I am using the responseBody string, but do not know where it came from? So is there documentation I am missing which shows these implicit items and values so that I am aware of what I can make use of in my test scripts? I have searched all over the learning center with no luck, Thanks!

Please refer to the Postman JavaScript reference to learn about what is available.