@kaleb Oh, I've got you on this one. This is what I do all day. :)

So follow your original link:

https://haugenh.us/kaleb/now_json.html

Right click on the page and choose 'Inspect'

Then go over to the 'Network' tab (screenshot). (This is chrome-like, but Firefox, etc, all are similar)

If you can't find the feed.rss request in there, refresh the page and now that the console is open, you'll see it load.

Click on it on the left, and you'll see it expand to give you more information about the request, including both request headers (that you're sending) and response headers.