I use an extension for Google Chrome to hide my IP (proxy), but Yandex still determines the real why?

Question

proxy

Here all sites show the ip of the proxy server, and yandex determines the real one. Extensions tried different yandex still calculates the real one as if there are no proxies.
The question is why is that?

Answer 1

Yandex executes the program code in the browser to get your real IP address bypassing the proxy. If you disable JavaScript, it will most likely not show your IP

Answer 2

I agree, but why can't others like https://2ip.ru do this. When you do an anonymity check, it says yes you are using a proxy, but we have not determined the real ip. Does Yandex have some kind of secret JS? Is it possible to disable JavaScript execution in the modern Internet?