What is an example of a self-describing file format?

A self-describing file format is one that contains metadata within the file that provides information about the file's structure, content, and the way it should be interpreted. The Portable Document Format (PDF) is a prime example of this. PDF files are designed to present documents, including text formatting and images, in a manner that is independent of the software, hardware, or operating systems used to create or view the document. Each PDF includes its own metadata and structural information, allowing programs to accurately render the document as intended by the creator.

In contrast, other file formats do not offer the same level of self-description. For instance, a ZIP file, while it encompasses multiple files and folders, relies on external file structures and does not embed detailed information about its content in a way that describes its structure or format inherently. Similarly, JPEG files primarily store image data and may contain some minimal metadata (like EXIF data), but they do not provide comprehensive self-describing capabilities as seen in PDFs. DOCX files do contain some structural information through XML, but it is less robust compared to the self-describing nature of a PDF, especially regarding content presentation and file integrity across various environments.