The Mozilla toolkit has a backend that uses the Qt application and UI framework from Nokia. There were several attempts at this prior to the current Mozilla code for Qt version 4.x.
As of February 2010 Mozilla Corp does not ship products using the Qt backend, but individuals have produced Firefox and Fennec builds using it. Search wiki.mozilla.org for engineers' notes on building software using this backend.
- Vladimir Vukićević describes the revived backend in 2008 (it has since been merged to mozilla-central).
- Archived Qt Mozilla ports page describing earlier 2003 Qt 2.x work