I'm learning frontend development and browsing through websites trying to learn from what is on the web. One thing that escapes me is that when I work locally I just make a fetch request to localhost:PORT/... to my backend but I wanted to see what it looks like in production websites, e.g. finding where they make the request + server URL.

How would one download all files from a webpage and then find where an HTTP request is being made in the code?

In my mind it's searching for fetch, XMLHttpRequest, axios or something similar.