interface EnsureOffscreenOptions {
    url: string;
    reasons: chrome.offscreen.Reason[];
    justification: string;
}
export declare function ensureOffscreen(opts: EnsureOffscreenOptions): Promise<void>;
/** Whether the offscreen document is currently up. Exported for the OAuth
 *  watcher, which must not *create* one — a fresh document holds no PKCE
 *  verifier, so there would be nothing to adopt. */
export declare function offscreenExists(url: string): Promise<boolean>;
export {};
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