This release brings forward a Unity Lens to access the clipboard history.
However when you build Diodon from source the Unity Lens will be disabled by default.
With the following command you can enable it:
./waf configure --enable-unity-lens
If you want to disable the Unity Lens when installing from the ppa, you have to remove the file /usr/share/unity/places/diodon.place.
In the future a plugin system is going to be implemented. This way the Unity Lens will be independently installable.