SonarQube has got a very efficient way of navigating, a balance between high-level view, dashboard, TimeMachine and defect hunting tools. This enables to quickly uncover projects and / or components that are in Technical Debt to establish action plans.
JMRTD is an open source Java implementation of the Machine Readable Travel Document (MRTD) standards as specified by the International Civil Aviation Organization (ICAO). The electronic passport (or "ePassport"), which by now has been introduced in many countries, is an implementation of these standards.
XWiki Enterprise is a professional wiki that has powerful extensibility features such as scripting in pages, plugins and a highly modular architecture.