export type Header = {
    readonly aIM?: string;
    readonly accept?: string[];
    readonly acceptCharset?: string[];
    readonly acceptDatetime?: string;
    readonly acceptEncoding?: string[];
    readonly acceptLanguage?: string[];
    readonly accessControlRequestMethod?: string;
    readonly accessControlRequestHeaders?: string;
    readonly authorization?: string;
    readonly cacheControl?: string;
    readonly cfConnectionIp?: string;
    readonly cfIpCountry?: string;
    readonly connection?: string;
    readonly contentLength?: string;
    readonly contentMD5?: string;
    readonly contentType?: string;
    readonly cookie?: string;
    readonly date?: string;
    readonly expect?: string;
    readonly forwarded?: string;
    readonly from?: string;
    readonly host?: string;
    readonly http2Settings?: string;
    readonly ifMatch?: string[];
    readonly ifModifiedSince?: string;
    readonly ifNoneMatch?: string[];
    readonly ifRange?: string;
    readonly ifUnmodifiedSince?: string;
    readonly maxForwards?: string;
    readonly origin?: string;
    readonly pragma?: string;
    readonly proxyAuthorization?: string;
    readonly range?: string;
    readonly referer?: string;
    readonly te?: string[];
    readonly trailer?: string;
    readonly transferEncoding?: string;
    readonly userAgent?: string;
    readonly upgrade?: string[];
    readonly via?: string[];
    readonly warning?: string;
    readonly upgradeInsecureRequests?: string;
    readonly xRequestedWith?: string;
    readonly dnt?: string;
    readonly xForwardedFor?: string;
    readonly xForwardedHost?: string;
    readonly xForwardedProto?: string;
    readonly xMsContinuation?: string;
    readonly frontEndHttps?: string;
    readonly xHttpMethodOverride?: string;
    readonly xAttDeviceId?: string;
    readonly xWapProfile?: string;
    readonly proxyConnection?: string;
    readonly xCsrfToken?: string;
    readonly xCorrelationID?: string;
    readonly xModNonce?: string;
    readonly xModRetry?: string;
    readonly saveData?: string;
    readonly xAuthToken?: string;
    readonly xTrackingId?: string;
} & Record<string, string | string[] | undefined>;
export declare namespace Header {
    function is(value: any | Header): value is Header;
    function to(header: Header): Record<string, string | undefined>;
    function from(headers: globalThis.HeadersInit): Header;
    function toString(header: Header): string;
}