RDAP and whois
RDAP is the newer of the two protocols. It returns a structured answer, and the list of servers comes from IANA, so the data is read from the registry that actually holds the domain. For the endings that have no RDAP service yet, .lv among them, the classic whois protocol is used instead.
The tool always shows which of the two answered and which server the answer came from, so a thin or unusual result can be traced back to its source.
Why the contact details are hidden
Since the data protection rules came into force, most registries no longer publish the contact details of private individuals. What stays public is the registration and expiry dates, the domain status, the registrar and the name servers. For companies, part of the registries still publish the name of the holder.
Where the contacts are withheld, many registries publish an anonymised relay address or a web form instead, and a request for the real data goes through the registrar.