export declare function assertOrigin(actual: string, expected: string): boolean;
/** Fail-closed precondition (H-F): the iframe must be cross-origin to the host so
 *  `allow-same-origin` can't reach host DOM, and `src` must be on the provider origin. */
export declare function assertCrossOrigin(src: string, providerOrigin: string, hostOrigin: string): void;
export declare function redactFrame(value: unknown): unknown;