It looks like someone didn`t buy enough copper fabric for the front of her quilt and had to do some creative filling out.
The fabric looks silver in the photos but is actually a beige colour.
A characteristic of Welsh quilting is that it pays little or no attention to the underlying pieced work. It`s difficult to make out but the corner fan is quilted across all three parts of the quilt. And this is the back. I don`t think you could pick a fabric better designed for hiding quilting stitches if you tried!