How can a bread have an expiration date of one year into the future?? The bread in questions is Deutsche Küche rye bread (from Aldi). Yes, it is a dense bread, but it is not dry like a cracker, so there seems to be enough moisture for mold to grow. There are no preservatives.
It's the baking and packaging.
These dark rye breads are baked for a very long time (effectively pasteurizing them) and then sealed in their packaging. If you do this in a commercial setting that can ensure a mostly contaminant-free environement, such breads can last a long time.
Once you break the seal by opening the pack, your bread will get moldy like all other breads.
The very dense crumb structure and compounds in the whole-grain rye used might to a certain degree inhibit the growth of mold, but not enough to make the bread last for months.