/**
 * @fileoverview Unknown PURL type (minimal implementation).
 *
 * The unknown type is used when the package type cannot be determined.
 * It has no specific normalization or validation rules beyond the base PURL spec.
 */
interface PurlObject {
    name: string;
    namespace?: string | undefined;
    qualifiers?: Record<string, string> | undefined;
    subpath?: string | undefined;
    type?: string | undefined;
    version?: string | undefined;
}
/**
 * Normalize unknown package URL.
 * No type-specific normalization for unknown packages.
 */
export declare function normalize(purl: PurlObject): PurlObject;
export {};