/**
 * Decode a SpreadsheetML `ST_Xstring` (§22.9.2.19): every `_xHHHH_` becomes the
 * character it names. Text carrying no escape is returned unchanged, so the
 * common path costs one failed match.
 *
 * @param text The raw `<t>` content.
 * @returns The text with its escapes resolved.
 */
export declare function decodeXstring(text: string): string;