The QXD file extension is the legacy proprietary file format used by QuarkXPress, a professional desktop publishing and page layout software application. Developed by Quark, Inc., these files contain complex page layouts, including text, imported images, vector graphics, typography settings, and color profiles. QXD files were the industry standard for print media production, such as newspapers, magazines, and brochures, throughout the 1990s and early 2000s. The format stores information about how elements are positioned on a page, as well as links to external assets like high-resolution images. Because QXD is a binary format specific to older versions of QuarkXPress, it is often considered a legacy format; modern versions of QuarkXPress have transitioned to the QXP extension. Opening these files often requires specific versions of the software, as newer iterations may have compatibility issues with legacy document structures.