QTWEBKIT_FROM_2_2 - >= 2.2.0 QTWEBKIT_TO_2_2 - < 2.2.0 QTWEBKIT_FROM_2_3 - >= 2.3.0 QTWEBKIT_TO_2_3 - < 2.2.0 It also check whether Qt5 is used and if so, it will compile all features just like the QtWebKit version was 2.3.0
Also hiding new features in preferences if building with older QtWebKit versions.