How to find out all the data that can be passed in a GET request?

Question

HTTP headers

One site makes a GET request like /abc?dfg=x&hij=y&......(and so on) to get data. The request address does not list all the parameters that can be sent. How to find out all the parameters that can be passed through &?

Answer 1

1. stupid enumeration of everything and everything
2. find the specification for the service api. If the api is for a wide range of users, there should be a page with a description