Gwenhywfar is a base library used to provide OS abstraction functions for Linux, FreeBSD, OpenBSD, NetBSD, and Windows. It also includes some often needed functions (for example, handling and parsing of configuration files, reading and writing of XML files, and interprocess communication).

Character entity sets for ISO 8879:1986.

JSON is a lightweight data-interchange format. It can represent numbers,
strings, ordered sequences of values, and collections of name/value pairs.

JsonCpp is a C++ library that allows manipulating JSON values, including
serialization and deserialization to and from strings. It can also preserve
existing comment in unserialization/serialization steps, making it a convenient
format to store user input files.

Kactivities provides an API for using and interacting with the Plasma Activities Manager.

Kactivities provides an API for using and interacting with the Plasma Activities Manager.

KCalendarCore is a library to provide access to and handling of calendar data.
It supports the standard formats iCalendar and vCalendar and the group
scheduling standard iTIP.

Utilities for interacting with KCModules

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.