This is beautiful, looks a little like Loyalist, but I am not the expert.
Leaves are too round to be an 'Undulata' so it could be 'Loyalist'. Whatever it is, some of it is reverting. If you like the white part of it, at some point you need to lift the plant and separate out the part that is going green. The all green leaves will grow faster than those with white centres and eventually that's all you'll have.
ViolaAnn - The green you see is apparently a piece of the next one over which I mixed up when I transplanted. I will divide it correctly this fall :)