XPath Explorer (XPE) is a GUI application that lets you interactively experiment with XPath. Basically, you type in a URL (to an XML or HTML document) and an XPath expression, and it displays the elements or attributes from that document which match that
Code Browser is a folding and outlining editor for Linux and Windows.
The editor is between a traditional text editor, a smalltalk class browser and a web browser like mozilla. It displays a structured text file (marker-based folding) hierarchically using multiple panes.
Codestriker is an open-sourced web application which supports online code reviewing. Traditional document reviews are supported, as well as reviewing diffs generated by an SCM (Source Code Management) system and plain unidiff patches. There are integration points with CVS, Subversion, Clearcase, Perforce, Visual SourceSafe and Bugzilla. There is a plug-in architecture for supporting other SCMs and issue tracking systems.
CSSToXSLFO is a utility which can convert an XML document, together with a CSS2 style sheet, into an XSL-FO document, which can then be converted into PDF, PostScript, etc. with an XSL-FO-processor. It has special support for the XHTML vocabulary, because that is the most obvious language it would be used for. The tool has a number of page-related extensions. It also comes with an API in the form of an XML filter.
Jacksum is a free and platform independent software for computing and verifying checksums, CRCs and message digests (known as hash values and fingerprints). "Jacksum" is a synthetic word made of JAva and ChecKSUM.
Geany is a text editor using the GTK2 toolkit with basic features of an integrated development environment. It was developed to provide a small and fast IDE, which has only a few dependencies from other packages. It supports many filetypes and has some nice features.