a perl interface to James Clark's XML parser, expat
XQuisitor is a simple GUI interface for XQuery based on Michael Kay's Saxon 8. XQuisitor is free software, written in Java, published under the GPL. It is an end-user application that has no public API (at least not yet).
xulfaces adds XUL power to Java via Java Server Faces with an XUL RenderKit, a custom XUL tag library, and Facelets support for increasing productivity.