libunibreak is an implementation of the line breaking and word breaking algorithms as described in Unicode Standard Annex 14 and Unicode Standard Annex 29. It is a superset of, and supersedes, liblinebreak. It is designed to be used in a generic text renderer. FBReader is one real-world example.
XSLT syntax highlighting is an implementation of syntax highlighting as an extension module for Java based XSLT processors (such as Xalan or Saxon). For example, if you have an article about programming written in DocBook, code examples can be automatically syntax highlighted during the XSLT processing phase.