Is this generated code? I don't know the reason for this particular comma, but I often write code generators that put a comma after each array element like the following:

Code:
int foo[] = {
  1,
  2,
  3,
};
so the code generator doesn't have to worry about whether each element is the last or if there are more following it. C and C++ allow the last element to have a comma after it which makes this possible (and convenient).