/**
 * Proxy handler for content-addressed release assets.
 *
 * Owns the `/_vf/assets/{hash}.{js|css}` prefix on the project's own domain.
 * Validates the hash + extension, fetches bytes from the API's public
 * `/release-assets/{hash}` endpoint, caches hot bytes in a small in-memory LRU,
 * and serves them immutable + nosniff with an allowlisted content type.
 *
 * The renderer is never involved.
 *
 * @module proxy/asset-handler
 */
/** True when the path is owned by the release asset prefix. */
export declare function isReleaseAssetPath(pathname: string): boolean;
export interface ReleaseAssetHandlerOptions {
    apiBaseUrl: string;
    /** Injectable fetch for tests. Defaults to global fetch. */
    fetchImpl?: typeof fetch;
    /** Bound for this caller's cold-load wait. Shared work may serve longer-lived callers. */
    timeoutMs?: number;
}
/**
 * Serve a release asset for the given request URL.
 *
 * @returns a Response on the asset path, or null if the path is not an asset
 * path (caller should continue normal forwarding). For invalid hashes/exts a
 * 400 is returned; for upstream 404s a no-cache 404 is returned.
 */
export declare function handleReleaseAssetRequest(req: Request, url: URL, options: ReleaseAssetHandlerOptions): Promise<Response | null>;
/** Clear the in-memory asset cache (tests / memory pressure). */
export declare function clearReleaseAssetProxyCache(): void;
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