WebKit was originally derived by Apple Inc. from the Konqueror browser�s KHTML software library for use as the engine of Mac OS X�s Safari web browser and has now been further developed by individuals from the KDE project, Apple Inc., Nokia, Google, Torch Mobile and others.
However, the exchange of code patches between the two branches of KHTML has previously been difficult and the code base diverged because both projects had different approaches in coding. One of the reasons for this is that Apple worked on their version of KHTML for a year before making their fork public.
Despite this, the KDE project was able to incorporate some of these changes to improve KHTML's rendering speed and add features, including compliance with the Acid2 rendering test. Konqueror 3.5 passed the Acid2 test, which was released after Apple had opened its WebKit CVS and Bug Database.