/**
 * handlers/fallback.ts — Tier-2 universal trailer handler
 *
 * Works on ANY file format. Appends a self-describing binary trailer:
 *   [original bytes][signature_json_utf8][8-byte length LE][8-byte magic]
 *
 * Files remain valid for their primary use — most parsers ignore trailing bytes.
 * The magic bytes allow detection and clean stripping from any file.
 */
import { FormatHandler } from "../types";
export declare class FallbackHandler implements FormatHandler {
    readonly name = "Fallback (Universal Trailer)";
    readonly supportedMimeTypes: readonly ["*/*"];
    canHandle(_bytes: Uint8Array, _mimeType?: string): boolean;
    embed(bytes: Uint8Array, signatureJson: string): Promise<Uint8Array>;
    extract(bytes: Uint8Array): Promise<string | null>;
    strip(bytes: Uint8Array): Promise<Uint8Array>;
}