export interface Relationship {
    /** rIdN identifier; unique within the parent .rels file. */
    id: string;
    /** Full relationship type URI. */
    type: string;
    /** Target — relative part path or absolute URL when targetMode === 'External'. */
    target: string;
    /** Defaults to internal. */
    targetMode?: 'External' | 'Internal';
}
export interface Relationships {
    rels: Relationship[];
}
export declare function makeRelationships(): Relationships;
/**
 * Append a relationship and return the resulting object. Auto-assigns the next
 * free `rId{N}` Id.
 */
export declare function appendRel(rels: Relationships, type: string, target: string, targetMode?: 'External'): Relationship;
export declare function findById(rels: Relationships, id: string): Relationship | undefined;
/**
 * Build an id → relationship index for callers that look up the same .rels
 * file many times in a hot loop. Cheaper than repeated {@link findById} once
 * the rels count crosses a handful of entries.
 */
export declare function indexRelsById(rels: Relationships): Map<string, Relationship>;
export declare function findByType(rels: Relationships, type: string): Relationship | undefined;
export declare function findAllByType(rels: Relationships, type: string): Relationship[];
export declare function relsToBytes(rels: Relationships): Uint8Array;
export declare function relsFromBytes(bytes: Uint8Array | string): Relationships;