This Alsatian specialty is what Alsace is famous for...also known as sauerkraut.
Except that it tastes lot different than German sauerkraut...
It's shredded cabbage fermented in salt water over a period of time. And before freezers and refrigerators, it was the only way to preserve it for winter.
It's often cooked with a Riesling white wine from Alsace, potatoes and other spices.