Unattached items is no longer used in Version 2.0 at all. That is why it is hidden.

Everything that is not attached to a playlist is still a valid tune in the player and can be played via a Search, and will appear in the Soup views in Emplode.

If you wish to see what the contents of Unattached Items would have been if it were visible, do an advanced search on "refs=0", that will get you the same results as looking at Unattached Items.