The IP lookup asks ipify (address) and ipapi.co (provider, location). Both are on the HaGeZi ULTIMATE list – if you run ULTIMATE, this page will show only what the server itself can see. Host it on Cloudflare Pages with the included function and it works regardless.
Questions, answered
Is my IP address private information?
It identifies your internet connection, not you personally, but combined with timestamps a provider can link it to a customer. That is why a VPN or a proxy changes what sites see.
Why does the location show a different city?
Geolocation databases map IP ranges to where the provider announces them. Mobile carriers and large ISPs often route everything through a few cities.
IPv4 and IPv6 – why two addresses?
Most connections have both. Websites use whichever the browser picks, usually IPv6 if available. A DNS filter has to cover both, otherwise a tracker can slip through via the other family.