From MEPIS Documentation Wiki
KDE (K Desktop Environment) is the powerful Free Software graphical desktop environment for Linux that constitutes the default desktop environment for MEPIS. It provides basic desktop functions and applications for daily needs (Kmail, Amarok, K3b, etc.) as well as development tools and user documentation.
KDE category — Mepis Wiki list of KDE topics
KDE4 — Mepis Wiki KDE4 topics