Bypassing the nepalstock.com site API

I am trying to access data here : https://nepalstock.com/company

This is what I see when I inspect in browser.

First the client js (frontend) requests an auth token from https://nepalstock.com/api/authenticate/prove.

I think then, some js code( running on frontend aka client side ) is internally manipulating this first token slightly. Only then the frontend calls this another https://nepalstock.com/api/nots/company/list endpoint with the updated accesstoken.

There are couple of js code I can see when I inspect. But don't know which one is doing the manipulation. Any help with this ?