XMLNuke is Web development framework based on XML. Programming with the XMLNuke framework, you create your Web site based on your data. Web design is not mandatory. To aid in this work, XMLNuke provides several classes for abstracting the use of XML and the environment in which XMLNuke is running. PHP5 or CSharp/Mono may be used by programmers to build applications with XMLNuke.
XMLUnit provides assertions and supporting class libraries to test various properties of generated pieces of XML using a popular testing framework. It supports finding the differences between two pieces of XML, validating documents against DTDs or XML Schemas, testing the results of XPath expressions, or asserting properties of Nodes exposed via DOM traversal. Two branches exist: one that supports Java and JUnit and one that supports the .NET Framework and NUnit.
XSockets is an open, lightweight, and highly portable library of universal and extensible super sockets for point-to-point communication. It provides a unified API for many communication methods between programs and devices. Currently, many methods of point-to-point communication are well established, like TCP/IP sockets, serial links, named pipes, infrared, or Bluetooth connections. XSockets is meant to provide a single API that can be used for of these methods and more.
Xapian is a search engine library, scalable to collections containing hundreds of millions of documents. It's written in C++ with bindings for Perl, Python, PHP, Java, Tcl, C#, Ruby, and Lua. It is a highly adaptable toolkit that allows developers to easily add advanced indexing and search facilities to their own applications. It supports the Probabilistic Information Retrieval model and also a rich set of boolean query operators. Omega is a Web search application built upon the Xapian library. It can index a Web server's document tree (including HTML, PDF, OpenOffice, MS Word/Excel/Powerpoint/Works, WordPerfect, RTF, PS, etc.), or data exported from arbitrary sources (e.g. SQL databases).
Yelo is a standalone service catalog for SOA (service-oriented architecture). A service catalog is an important part of the business process of service-oriented architecture and seems to be available today only as part of a larger package. This application is meant to foster a "marketplace" approach to services within an enterprise.