I found a lot of shipping attributes. We found with Hyo Jeong Chang it was created automatically from sears listings.
It looks like Marchello And Co.-SKU-NUMBER
Property Type = Shipping
example SKU: SKU-NUMBER
So it will create shipping attribute for each sears listing. And when you need to add all extended attributes in export it will add all this shipping attributes.
If you can't avoid creating this probably you can divide «add all extended properties» and «add shipping attributes». So in this case it will not shows when I'm doing export.