KDE stands for K Desktop Environment. Qt can be significantly experienced on a KDE desktop. The Qt toolkit was used for the KDE project. Every window available on the KDE desktop is a part of the Qt design.
Actually KDE is primarily built on several technologies such as
- KHTML - an HTML engine
- Plasma - desktop and panel widget engine
- Phonon - multimedia framework
- Solid - device integration framework
On top of this the entire UI is built on the technology of KDELibs, which is in turn built on Qt.