A registrar is the intermediary you pay to reserve a domain name on your behalf. They don't own the infrastructure—that's the registry. They handle the paperwork, the WHOIS record, the EPP authcode, renewal reminders, and the bureaucracy that ICANN imposed on the whole system.
Most registrars are creatures of compliance. They ask questions, log your data, reply to DMCA notices within 24 hours, and freeze domains on a subpoena. Some registrars—including bunkerdomains—skip the theater. We don't require KYC, we don't log your registration IP, we don't forward takedown notices, and we accept crypto so you don't have to give a payment processor your identity.
Registrar choice matters more than TLD choice if you value privacy. A .com domain at a privacy-hostile registrar is still exposed. A .is domain at an anonymous registrar actually stays anonymous. Check their WHOIS policy, their DMCA response rate (or non-response rate), their payment methods, and whether they'll hand over your data to courts in jurisdictions you don't live in.