/**
 * Parses a query string into an object of key-value pairs.
 *
 * @param queryString - The query string to parse. It may include a leading '?' which will be removed automatically.
 * @returns An object where keys are query parameter names and values are either a string or an array of strings if the parameter appears multiple times.
 *
 * @example
 * ```typescript
 * const queryString = '?foo=bar&baz=qux&foo=baz';
 * const result = parseQueryString(queryString);
 * console.log(result);
 * // Output: { foo: ['bar', 'baz'], baz: 'qux' }
 * ```
 */
export declare const parseQueryString: (queryString: string) => Record<string, string | string[]>;