What are these directories?
These are official packages that go in the Debian distribution
which are made available here by the maintainer.
Packages which have been taken from the woody distribution "as is"
because they fixed some bugs in the potato packages.
Packages which have been backported from woody into potato. Care has
been taken that the packages will be upgraded without problems to the
real woody packages. These packages fix problems in the potato packages.
These have been improved with some aditional functionality.