Wikipedia
The domain name int is a sponsored top-level domain (sTLD) in the Domain Name System of the Internet. Its name is derived from the word international, characterizing its use for international organizations and treaty-related purposes. The first use of this domain was by NATO, which had previously been assigned the top-level domain nato.
According to Internet Assigned Numbers Authority (IANA) policy, based on RFC 1591, the sTLD int is reserved for international treaty-based organizations, United Nations agencies, and organizations or entities having observer status at the UN. int is considered to have the strictest application policies of all TLDs, as it implies that the holder is a subject of international law. For this reason, the application procedure requires the applicant to provide evidence that it is indeed treaty-based by providing a United Nations treaty registration number and that it has independent legal status.