Libxml2 is the XML C library developed for the Gnome project. The library code is portable (to Linux, Unix, Windows, embedded systems, etc.) and modular; most of the extensions can be compiled out. Libxml2 implements a number of existing standards related to markup languages, including the XML standard, Namespaces in XML, XML Base, Relax NG, RFC 2396, XPath, XPointer, HTML4, XInclude, SGML Catalogs, and XML Catalogs. In most cases, libxml tries to implement the specifications in a relatively strict way. To some extent, it provides support for the following specifications, but doesn't claim to implement them: DOM, FTP client, HTTP client, and SAX2. Support for W3C XML Schemas is in progress. It includes xmllint, a command line XML validator.
Libxslt is a C library for GNOME which allows developers to work with XSLT. It is based on libxml for XML parsing, tree manipulation, and XPath support. Also included is 'xsltproc', a command line XSLT processor. The library is written in plain C, making as few assumptions as possible, and sticking closely to ANSI C/POSIX for easy embedding. It should work on Linux, Unix, and Windows. Though not designed primarily with performances in mind, libxslt seems to be a relatively fast processor. It also include full support for the EXSLT set of extension functions as well as some common extensions present in other XSLT engines.
ZenWeb is a system for building entire Web sites, not just pages. It allows you to focus on the content and the structure of the website, while leaving page construction, markup, layout, and navigation as secondary concerns. It provides tools for complete Web site design and creation, simple paragraph to HTML generation with embellishments, and a rich set of tools for page and Web site creation, modification, and customization.
Richie Rich is an HTML document editor that runs within a Web browser. Unlike other in-line HTML editors, this operates straight on the DOM to avoid incongruities between what is visible in the front end and the HTML that is created in the back end. It supports undo, mouse selection, cursor positioning, and creation of headings, paragraphs, lists, links, bold, italic, and underline.
Aranha is a piece of software written to allow Web applications to be written more cleanly and more easily. It is a Local FastCGI Responder, although work is in progress to allow it to work as a FastCGI Authoriser and a FastCGI Filter. It is based on the programming language Lua, and contains many extensions to enable easy Web site development and maintenance.