-The default is to diff against our branch (-2) if there
-is an unmerged path, and show diff for unmerged entries
-otherwise. The option -0 can be given to force diff for
-unmerged entries even when the index is unmerged.
+The default is to diff against our branch (-2) and the
+cleanly resolved paths. The option -0 can be given to
+omit diff output for unmerged entries and just show "Unmerged".
+
+-c,--cc::
+ This compares stage 2 (our branch), stage 3 (their
+ branch) and the working tree file and outputs a combined
+ diff, similar to the way 'diff-tree' shows a merge
+ commit with these flags.