import type { TadamXCallbackPayload } from './shared';
/**
 * Open Tadam URL scheme documentation through the documented x-callback-url prefix.
 *
 * @param payload Tadam x-callback-url payload.
 * @returns Tadam x-callback-url help URL.
 * @example
 * xCallbackHelp()
 * // => 'tadam://x-callback-url/help'
 * @link https://tadamapp.com/url-schemes/
 */
export declare function xCallbackHelp(payload?: TadamXCallbackPayload): string;