What features are cursor controlled on the A380 Navigation Display?
This is what the KCCU looks like:


Source: A380-800 Flight Deck and Systems Briefing for Pilots

Each KCCU is connected to its FMS:


Source: A380-800 Flight Deck and Systems Briefing for Pilots

From the Airbus booklet cited above:


  The flight crew uses the KCCU to:
     • Navigate through the FMS pages on the MFD
     • Enter and modify data on the MFD
     • Perform some flight plan revisions on the lateral ND.


And:


  The KCCUs enable the flight crew to directly interact with the onside
  ND, MFD and the mailbox section of the SD.


The KCCU can be used, for instance:


  
  To select an airport 
  To navigate throughout the Airport Moving Map (drag technique) 
  To set some marks (flags and crosses) for drawing a path 
  To activate the correct database.
  


(source: Getting to grip with surveillance

This figure shows what is reachable with the KCCU:


Source: A380-800 Flight Deck and Systems Briefing for Pilots

As there are two KCCU:


  Each KCCU displays a different cursor. If both cursors are displayed
  on the SD, only one can be active.


There is a functional redundancy between the keyboard and the cursor control unit.

The Onboard Airport Navigation System which displays a moving airport navigation map, is also accessible using the KCCU interactively.

You may also have a look at the book Introduction to Avionics Systems:


  The Multi-Function Display (MFD) displays textual data; over 50 FMS
  pages provide information on the flight plan, aircraft position and
  flight performance. The MFD is interactive; the flight crew can
  navigate through the pages and can consult, enter or modify the data
  via the Keyboard and Cursor Control Unit (KCCU). 
  
  The Keyboard and
  Cursor Control Unit (KCCU) enables the flight crew to navigate through
  the FMS pages on the MFD and enter and modify data on the MFD, as
  mentioned above, and can also perform some flight plan revisions on
  the lateral Navigation Display (ND).