Q.What are the contents of a DB backup ?

A. The items contained are dependant on the backup method , such as database or TABLESPACE

Use the backup utility : db2ckbkp  to interrogate the contents of a DB2 backup.  db2ckbkp checks integrity and displays meta information

 For example, if you use the –a   switch this will display all available meta information

       #The example used below  displays the table space details
      
        db2ckbkp -a MYDB.0.db2db2.NODE0000.CATN0000.20120305152355.001
    
      #  The following example displays the table space details 

      #db2ckbkp -t MYDB.0.db2db2.NODE0000.CATN0000.20120305152355.001
    

See Also
DB2 – Restore database from a ONLINE backup