WebCore is a framework developed by Apple, and licence under the LGPL, to provide an HTML layout engine for Mac OS X. It is one half of WebKit (the other being JavaScriptCore). WebCore combines the open source KHTML layout engine developed by the KDE project, with an adapter library called KWQ (pronounced Quack). Apple created the KWQ adapter to replace KHTML's dependency on code from the Qt toolkit and other KDE modules. KWQ also presents an Objective-C application programming interface to the C++-based KHTML rendering engine, allowing it to easily be referenced by Cocoa-based applications.