/**
 * Map a legacy item id (optionally with a Bedrock pre-flattening data value)
 * to its modern flattened identifier. Returns the input id unchanged when
 * there is no known mapping.
 */
export declare function resolveLegacyItem(id: string | undefined, data?: number): string | undefined;
/**
 * Convenience: returns true if `id` is a known legacy (pre-flattening) item.
 * Useful for tests and validation messages.
 */
export declare function isLegacyItemId(id: string | undefined): boolean;