References to older Qt versions in 4.2.0 diff.gz

I am looking at the qt4-x11_4.2.0-1ubuntu6.diff file and I see patches for:

qt4-x11-4.0.1/src/corelib/global/qglobal.h
qt4-x11-4.1.0/src/corelib/arch/parisc/q_ldcw.s
qt4-x11-4.1.0/src/corelib/arch/mips/qatomic32.s
qt4-x11-4.1.3/src/opengl/opengl.pro
/home/nelson/tmp/dpep-work.Zny9K3/qt4-x11-4.0.1/tools/assistant/lib/qassistantclient.cpp`
qt4-x11-4.1.3/src/corelib/global/qlibraryinfo.cpp

and so on.

What are patches for older versions of Qt doing in the 4.2.0 diff file?
Surely this diff is intended to be applied to the 4.2.0 source only?

Shriramana Sharma.