Comment 4 for bug 458872

Confirmed. It seems that even packages you installed manually using dpkg -i or GDebi are considered as obsolete. This means from the moment you installed them, CJ wants to remove them. I guess there's a way to find out whether they were installed from a repository that is now disabled, or if the user explicitly installed them.

One of the common errors I can see with this is libdvdcss2, which most people install to read DVDs. It's installed by the script in /usr/share/doc/libdvdread4/install-css.sh: users don't know they need it, and removal may break their encrypted DVDs support without noticing.