Except, you'll note that the array is actually DEFINED as a free variable (not part of the class) in the header file, not just DECLARED. Since this file #include(d) in the .ino, the variable should be available there. This is really BAD coding practice and makes me wonder about the quality of the entire library.
EDIT:
But, since it's static, there will be two different arrays allocated. One in the library's .cpp and one in the main .ino. Looks sketchy to me.