This excerpt taken from the VRSN 10-K filed Jul 12, 2007.
Whois Provider Data Specification
Registry Operator shall provide bulk access to up-to-date data concerning domain name and nameserver registrations maintained by Registry Operator in connection with the Registry TLD on a daily schedule, only for purposes of providing free public query-based access to up-to-date data concerning domain name and nameserver registrations in multiple TLDs, to a party designated from time to time in writing by ICANN. The specification of the content and format of this data, and the procedures for providing access, shall be as stated below, until changed according to the Registry Agreement.
The data shall be provided in three files:
A. Domain file. One file shall be provided reporting on the domains sponsored by all registrars. For each domain, the file shall give the domainname, servername for each nameserver, registrarid, and updateddate.
B. Nameserver file. One file shall be provided reporting on the nameservers sponsored by all registrars. For each registered nameserver, the file shall give the servername, each ipaddress, registrarid, and updateddate.
C. Registrar file. A single file shall be provided reporting on the registrars sponsoring registered domains and nameservers. For each registrar, the following data elements shall be given: registrarid, registrar address, registrar telephone number, registrar e-mail address, whois server, referral URL, updateddate and the name, telephone number, and e-mail address of all the registrars administrative, billing, and technical contacts.
The format for the above files shall be as specified by ICANN, after consultation with Registry Operator.
Procedures for Providing Access
The procedures for providing daily access shall be as mutually agreed by ICANN and Registry Operator. In the absence of an agreement, the files shall be provided by Registry Operator sending the files in encrypted form to the party designated by ICANN by Internet File Transfer Protocol.