I just found the ingredients and it says they use a flour tortilla.
INGREDIENTS
TACO: Filling: Water, Beef, Textured Vegetable Protein [Soy Flour, Caramel Color, Zinc Oxide, Ferrous Sulfate, Niacinamide, Calcium Pantothenate, Pyridoxine Hydrochloride (B6), Riboflavin (B2), Thiamine Mononitrate (B1), Vitamin A Palmitate and Cyanocobalamin...