The nutty name you're thinking of is "Swagger" - I think... 🤔
After selecting "Try it out", the interface should provide drop downs and text boxes for values appended to the URL string as well as present the JSON body in an editable text box. You can look at the Model to see what's required, minimum, etc. I usually copy/save the example JSON (as a comment in code) to keep the full body then edit out what I don't need and give it a run to see the results. After execution, Swagger will show you the curl command and full URL for the request and the results.
I do wish it allowed the addition of query fields on the URL but you can always run those separately in the browser or with curl (or Postman).
The "Features for all ONTAP APIs" section at the top is well worth a read.