A biorefinery can mean just about anything. After all, even new pulp mills have been called biorefineries.
Leuna is a chemical plant and doesn’t produce fibers. Borregaard also produces fibers, so some purist might argue that it’s neither a biorefinery nor a chemical plant.
The whole point of a biorefinery is that it outputs multiple products, not just pulp. Integrated oil refineries produce up to thousands of different products.