import type { ManifestAttribute } from './migration-types.js';
/**
 * Detect whether a default value changed between two manifest attribute snapshots.
 *
 * A change in `hasDefault` (a default appearing or disappearing) or a change in
 * the projected default value itself both count as default changes. Attributes
 * without defaults on either side are considered unchanged.
 *
 * @param oldAttribute Legacy manifest attribute snapshot.
 * @param newAttribute Current manifest attribute snapshot.
 * @returns True when the default value differs between the two snapshots.
 */
export declare function hasDefaultChange(oldAttribute: ManifestAttribute, newAttribute: ManifestAttribute): boolean;
/**
 * Describe a default value change for diff output.
 *
 * @param oldAttribute Legacy manifest attribute snapshot.
 * @param newAttribute Current manifest attribute snapshot.
 * @returns A human-readable description of the default value transition.
 */
export declare function describeDefaultChange(oldAttribute: ManifestAttribute, newAttribute: ManifestAttribute): string;