import { type JsonObject } from "type-fest";
type ErrorObject = {
    name?: string;
    stack?: string;
    message?: string;
    code?: string;
} & JsonObject;
export declare const __webextMessenger = true;
export declare function isObject(value: unknown): value is Record<string, unknown>;
export declare class MessengerError extends Error {
    name: string;
}
export declare class ExtensionNotFoundError extends MessengerError {
    name: string;
}
export declare function isErrorObject(error: unknown): error is ErrorObject;
export declare function delay(milliseconds: number): Promise<void>;
export declare function once<Callback extends (...arguments_: unknown[]) => unknown>(function_: Callback): Callback;
export {};