import type JSZip from 'jszip';
/**
 * Merges passive extension markup from source settings into generated settings.
 *
 * WordprocessingML settings and relationship-bound markup remain generated-only.
 * The source contribution is limited to ignorable extension attributes/elements
 * and structurally valid, non-conflicting mc:AlternateContent blocks, plus a
 * strictly validated color-scheme mapping required by preserved theme colors.
 */
export declare function preserveDocxSettingsExtensions(generated: JSZip, source: JSZip, generatedPath?: string, sourcePath?: string): Promise<void>;