xCHM is a cross-platform GUI frontend for CHMLIB, written with wxGTK. It is able to display the topics tree, work with displayed pages history, print the current page, work with bookmarks, change fonts and fast search through all the pages of the loaded .chm document. Being indirectly dependent on GTK+, the possibility of changing GTK+ skins makes xCHM theme-friendly.
xSiteable is a complete all-you-need package for creating sites that are fully relational, open source, fully templating-enabled, using only XML-based technologies to help you create complex sites on the fly. It packs such features as topic maps, notation for content, and the fast Sablotron xslt parser.
xbaydns provides a Web management interface for BIND 9. Its user-friendly Web interface is based on the Django framework. It has been tested on many OSes, including FreeBSD, Linux, and MacOS X Leopard. It provides an easy-to-use Web interface for DNS record management while implementing most of the advanced features provided by BIND.
xd3d is a simple scientific visualization tool designed to be easy to learn. It can plot 2D and 3D meshes, with shadowing, contour plots, vector fields, iso-contour (3D), as well as 3D surfaces z=f(x,y) defined by an algebraic expression or a cloud of points. It generates high-quality vector PostScript files for scientific publications and still or animated bitmap images. The distribution includes the graph plotter, xgraphic.