The problem is that gnome-screensaver is listed in the RequiredComponents for GNOME Flashback.
We should first check whether that's actually necessary for Flashback to work with gnome-screensaver.
It it is, I think it's possible to use Debian's alternative system to have a generic screensaver package that could be listed in RequiredComponents and then have gnome-session-flashback depend on any one of the packages that provide the generic screensaver functionality.
The problem is that gnome-screensaver is listed in the RequiredComponents for GNOME Flashback.
We should first check whether that's actually necessary for Flashback to work with gnome-screensaver.
It it is, I think it's possible to use Debian's alternative system to have a generic screensaver package that could be listed in RequiredComponents and then have gnome-session- flashback depend on any one of the packages that provide the generic screensaver functionality.