If you weren't, er, color perceptually challenged, you might have seen that is was a red wine reduction, as in
Food Network Award Winning "For the Love of Mushroom"
BE AWARE. THIS IS NOT A TRADITIONAL PIZZA. - A Rich and Filling pizza on a Whole Wheat blended crust with a White Sauce, a Garlic/Herb/ Mushroom sauté, Mozzarella & Provolone cheeses Garnished by a Flavorful Red Wine reduction. (No Red Sauce) This pizza was created for a food competition and has been described by YELP reviewers as thick as stroganoff or a thick, crunchy, "lasagnaish" filling on a crust.