/**
 * HTTP/2 SETTINGS frame fingerprints for server implementation identification.
 *
 * When an HTTP/2 connection is established, the server sends a SETTINGS frame
 * (RFC 7540 Section 6.5) containing its preferred protocol parameters. Different
 * HTTP/2 implementations choose distinct default values and orderings for these
 * settings, creating a reliable passive fingerprint.
 *
 * Additionally, idle connection GOAWAY behavior (timeout duration and debug data)
 * varies across implementations, providing a secondary identification signal.
 *
 * SETTINGS frame parameters (RFC 7540 Section 6.5.2):
 *  - HEADER_TABLE_SIZE      (0x1) - HPACK dynamic table size
 *  - ENABLE_PUSH            (0x2) - Server push enabled (0 or 1)
 *  - MAX_CONCURRENT_STREAMS (0x3) - Max simultaneous streams
 *  - INITIAL_WINDOW_SIZE    (0x4) - Flow-control window size
 *  - MAX_FRAME_SIZE         (0x5) - Largest frame payload
 *  - MAX_HEADER_LIST_SIZE   (0x6) - Max header list size
 *
 * References:
 *  - RFC 7540 (HTTP/2)
 *  - https://github.com/AliasIO/wappalyzer
 *  - https://www.blackhat.com/docs/eu-17/materials/eu-17-Shuster-Passive-Fingerprinting-Of-HTTP2-Clients-wp.pdf
 */
/** HTTP/2 SETTINGS frame signature for a known server implementation. */
export interface H2Signature {
    /** Server or implementation name */
    server: string;
    /** Expected SETTINGS frame parameters (undefined means the setting is not sent) */
    settings: {
        /** HPACK header table size in bytes */
        headerTableSize?: number;
        /** Whether server push is enabled (0 = disabled, 1 = enabled) */
        enablePush?: number;
        /** Maximum number of concurrent streams */
        maxConcurrentStreams?: number;
        /** Initial flow-control window size in bytes */
        initialWindowSize?: number;
        /** Maximum frame payload size in bytes */
        maxFrameSize?: number;
        /** Maximum header list size in bytes */
        maxHeaderListSize?: number;
    };
    /** Idle timeout in seconds before the server sends GOAWAY */
    goawayTimeout?: number;
    /** Expected content of the GOAWAY debug data field */
    goawayDebugData?: string;
}
export declare const H2_SIGNATURES: H2Signature[];
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