Use aptitude. It will allow you to visually browse all packages, read descriptions, (You would be able to see that kde is a virtual package...) and easily follow the dependencies around and see whats going on. Its served me well in untangling bizzare dependency problems. And it has the apparently unique feature of tracking which packages you've specifically asked to install, and those that were installed to fill a dependency. It'll ask you if you want to remove the packages when they are no longer depended upon, which helps combat cruft. I use aptitude exclusively. Even on Fedora... Or maybe try Synaptic if you want GUI