/**
 * Returns true if the value is a valid internationalized (IDN) hostname.
 * @specification https://tools.ietf.org/html/rfc3490
 * @specification https://tools.ietf.org/html/rfc5891
 * @specification https://tools.ietf.org/html/rfc5892
 * @specification https://tools.ietf.org/html/rfc5893
 */
export declare function IsIdnHostname(value: string): boolean;