Not sure what WHOIS is? CENTR have released an Issues Paper that explains. But in short, “the WHOIS tool is an important query and response protocol within the DNS system. It is essentially a tool allowing users to perform searches on a given domain (or IP address) and retrieve domain registration information.”
CENTR is an association of Internet Country Code Top Level Domain Registries with a European focus.
The CENTR paper aims give an introductory explanation to WHOIS and discuss the main issues surrounding it and is available for download at https://www.centr.org/main/6142-CTR/version/2/part/12/data/paperwhois.pdf