export declare function prefetchOriginsFromCDN(): Promise<void>;
/**
 * @internal
 * Limited to Microsoft-internal use
 *
 * Exported so the JSON validation can be unit tested directly.
 */
export declare function isValidOriginsJSONValid(validOriginsJSON: string): boolean;
/**
 * @internal
 * Limited to Microsoft-internal use
 */
export declare function validateOrigin(messageOrigin: URL, disableCache?: boolean): Promise<boolean>;
/**
 * @internal
 * Limited to Microsoft-internal use
 *
 * This function is only used for testing to reset the valid origins cache and ignore prefetched values.
 */
export declare function resetValidOriginsCache(): void;