The lxml XML toolkit for Python
XML editor
Fast XML parser library in C
Development toolkit for Web Services and XML data bindings for C & C++
Download, save and convert multiple subtitles from YouTube videos
X3D is the open-standard format for 3D graphics scenes on the Web.
XMLJ is a Java XML Editor and validator project.
Minimalistic address book in web browser. No server or plugin needed.
Web Application Server Stack for Delphi/FreePascal/Lazarus
Production space for the TEI Linguistics SIG
EasyML serialization library, to and from XML, similar to Gson
XML text markup for ancient documents
XML Schema for questionnaires and PDF questionnaire generator
Simple C++ XML processing
eXist-db is a feature rich Open Source native XML database
Simulatoralive's Java libraries and programs