What do you have in mind for general problems? I don't recall anything that doesn't apply to any particular package (other than things like #242950, which were filed on the "general" virtual package).
For general problems which affect only kfreebsd-any, for which there is not appropriate package. It might be used for blocking bugs (see #322762, for us i.e. unconditional selinux, alsa), missing infrastructure changes. And in mean time also for not-yet-in-unstable packages. The BTS on alioth is not much used. Petr