/**
 * @param {string} str
 * @returns {string}
 */
export function lower(str: string): string;
/**
 * @param {string} str
 * @param {number} [maxLen]
 * @returns {string}
 */
export function trim(str: string, maxLen?: number): string;
/**
 * @param {string|undefined} version
 * @returns {string|undefined}
 */
export function majorize(version: string | undefined): string | undefined;
/**
 * @param {string} ua
 * @returns {string}
 */
export function sanitizeUA(ua: string): string;
/**
 * @param {string} header
 * @returns {Array<{brand: string, version: string}>|undefined}
 */
export function parseBrandList(header: string): Array<{
    brand: string;
    version: string;
}> | undefined;
/**
 * @param {string} header
 * @returns {string|undefined}
 */
export function parseHeaderValue(header: string): string | undefined;
/**
 * @param {string} str
 * @param {Record<string, string|string[]>} map
 * @returns {string|undefined}
 */
export function mapStr(str: string, map: Record<string, string | string[]>): string | undefined;