Here you can see the domain registry data of aeat.es, but it's possible that the whois server only shows the data partially or perhaps it require you to access to its official website for more information. It's also possible that the data could be hidden or masked if the domain owner is using a privacy service.
The domain data shown here ARE PUBLIC and aren't hosted in our database. The ICANN (Internet Corporation for Assigned Names and Numbers) is who allows domains registrars to show, through a public WHOIS service, all or part of the domain registry data.
If you are a domain owner and you want to hide your personal data, there are several domain registrars that provide privacy services in order to hide your real registry data. Contact your registrar for more info.