/**
 * Serializes a DocumentFragment into HTML string.
 *
 * If fragment contains no element nodes,
 * returns textContent to avoid encoding issues.
 */
/**
 * @param {DocumentFragment} fragment - fragment to serialize.
 * @param {Document} doc - document reference.
 * @returns {string} - Serialized string
 */
export declare function serializeFragment(fragment: DocumentFragment, doc: Document): string;
