How to determine from the extension that the browser uses a proxy?

Question

JavaScript

The task is to determine the real ip of the site accessed by the browser. Or at least determine that the discovered ip is not correct.
If the browser is using a proxy, then the site's ip changes, as it were.
So far, I see a way - to remember somewhere in the extension the list of ip proxy servers, and if the ip of the site matches the ip of the proxy, then a proxy is used. But the problem is that there are countless proxies, and they are constantly changing, old ones die, new ones are created.
Is there a way to know that the current tab is actually being proxied and not accessing the site directly? Something like isUsedProxy(tabId) or isProxy(ip)

Answer 1

https://developer.chrome.com/extensions/proxy