I work a lot with JSON endpoints and having a browser extension to pretty print the JSON response is invaluable. However, sometimes I’m using a different machine (or guiding someone on their machine) and rather than asking them to install a browser extension, I use this trick. If the user is on the page displaying the JSON response, running this command in the browser console will pretty print the response await (await fetch(window.location.href)).json().
web browser
How to Run Code in the Browser Console
As a developer, a trick I often use is running some JavaScript directly in the browser to confirm the behavior.