RDAP source
https://rdap.nic.cz
port 43: whois.nic.cz
The registry blocks changes to the domain.
The registry blocks transfers. Often set for valuable or disputed domains.
Signed delegation in place.
WHOIS source
whois.nic.cz
REG-GRANSY REG-INTERNET-CZ REG-INTERNET-CZ REG-INTERNET-CZ REG-INTERNET-CZ REG-INTERNET-CZ
SvetHostingu.cz s.r.o. Libor Holub NETtip
Make a direct request at ICANN.