What feature of a document provides an overview of its contents?

The feature of a document that provides an overview of its contents is the table of contents. It is designed to give readers a clear roadmap of the document, listing the titles of sections or chapters along with their corresponding page numbers. This allows readers to quickly locate specific topics or sections they are interested in, enhancing the usability of the document.

The appendix, on the other hand, is usually found at the end of the document and contains supplementary material that supports the main content but does not provide an overview of the document itself. The index is a detailed alphabetical listing of topics, terms, or names found within the document, helping readers find specific information, but it does not summarize the document's layout. An abstract is a brief summary of the entire document, often used in academic papers, but it is not a structural overview that delineates the organization of the content as a table of contents does.