kcontacts is a Qt5 based library which provides an API
to access address book data stored in different formats.

KDE Daemon

KDNSSD is a library for handling the DNS-based Service Discovery Protocol
(DNS-SD), the layer of Zeroconf that allows network
services, such as printers, to be discovered without any user intervention or
centralized infrastructure.

KEmoticons

A library for extracting file metadata.

This package contains a library which helps developers determining when holidays occur.

KHtml

This framework provides additional image format plugins for QtGui. As
such it is not required for the compilation of any other software, but
may be a runtime requirement for Qt-based software to support certain
image formats.