% dose-builddebcheck --deb-native-arch=amd64 --dump=cudf Packages.bz2 Sources.bz2 native-architecture: amd64 background-packages: 55890 foreground-packages: 18109 broken-packages: 60
However, the file Source.bz2 contains more source packages than that:
% grep -c ^Package: Sources 18375
That means that 266 source stanzas have not been taken into account.
These packages were ignored because they have an architecture different from amd64. In the invocation above the target distribution is amd64 and therefore packages, for example, that should be compiled on armel only are ignored. Adding -v -v will show you the list of packages that are ignored.