Why RDAP instead of old WHOIS?
RDAP returns structured registration data over HTTPS and is the authoritative registration-data protocol for generic top-level domains. This page extracts common fields such as registrar, creation and expiration dates, status values, nameservers and DNSSEC.
The query leaves this site only when you explicitly press Lookup. The remote registry or RDAP service can see the lookup request, as with any registration-data client.