What Alsatian Wine/Grape can be legally labeled as a completely different wine?

In Alsace near the German border, where wine is typically labeled according to the grape rather than the place, a wine can be labeled “Pinot Blanc” and yet be 100% Auxerrois Blanc, an entirely different grape!

It could also be a mixture of Auxerrois, Pinot Gris (Grigio), Pinot Noir and Pinot Blanc. Or just Auxerrois, Pinot Gris and Pinot Noir, without any Pinot Blanc.

Enough said.