libhtml is a minimal C library for parsing, serializing, and manipulating HTML-4.01-strict and XHTML-1.0-strict documents. You may enjoy this library if you're interested in tight correctness of input and output data.
Open source project that offer summary and download services on this page is a project that carry out their development work on other open source development sites. Their work is linked to this page via a feature called OFI, and their work is not carried out here on OSDN site.