/**
 * Locates a browser to run Lighthouse audits in.
 *
 * `chrome-launcher` only looks for Google Chrome and Chromium. Plenty of people
 * run Arc, Brave or Edge and have no Chrome at all — for them every audit
 * failed with "No Chrome installations found", losing four of the fifteen tools
 * with no hint that a different browser would do.
 *
 * Any Chromium-based browser can serve, since Lighthouse only needs a DevTools
 * protocol endpoint. Preference runs from closest-to-stock outwards, because
 * the more a fork customises its UI the likelier a headless run is to surprise.
 */
export declare class NoBrowserError extends Error {
    constructor(message: string);
}
export interface BrowserCandidate {
    name: string;
    path: string;
}
export interface FoundBrowser extends BrowserCandidate {
    /** How it was located, for diagnostics. */
    source: "CHROME_PATH" | "chrome-launcher" | "known-install";
}
/**
 * Chromium forks worth trying, best first. Ordering matters: a stock-ish build
 * behaves most predictably under Lighthouse, and Arc customises the most.
 */
export declare const CHROMIUM_CANDIDATES: readonly BrowserCandidate[];
/**
 * Tried only once everything else is exhausted.
 *
 * Arc replaces much of Chromium's window and tab handling, so it is the most
 * likely to behave unexpectedly headless. It is still far better than failing
 * outright for someone who has nothing else installed.
 */
export declare const LAST_RESORT_CANDIDATES: readonly BrowserCandidate[];
export interface FindOptions {
    env?: NodeJS.ProcessEnv;
    exists?: (candidate: string) => boolean;
    /** chrome-launcher's own detection, injected so this stays testable. */
    installed?: () => string[];
    /** Additional paths to consider before the known forks. */
    extraCandidates?: BrowserCandidate[];
}
export declare function findAuditBrowser(options?: FindOptions): FoundBrowser;
/**
 * Explains a browser that was found but would not start.
 *
 * Lighthouse reports this as a bare "connect ECONNREFUSED <port>", because from
 * its side the debugging port simply never opened. That tells a user nothing.
 */
export declare function describeLaunchFailure(browser: FoundBrowser, cause: string): string;