Are the ingredients of the Big Mac's "Special Sauce" a secret? If not, what are they?

From a couple of recipe websites: 1 c. Miracle Whip
1/3 c. creamy style French dressing (3/4 cup vegetable oil or olive oil, 1/4 cup lemon juice, 1 tablespoon sugar, 3/4 teaspoon salt, 1/4 teaspoon paprika, 1/4 teaspoon dry mustard, 1/4 teaspoon pepper & 1/4 cup sour cream)
1/4 c. sweet pickle relish
1 tbsp. saugr
1 tsp. dried minced onion
1/4 tsp. pepper

I once knew a couple of guys that had worked at two different McDonalds. They both told me that the "Special Sauce" is thousand island dressing.

Thousand Island Dressing. Test it you will see.

It's just thousand Island dressing of a sort. There are all sorts of websites with the recipe.

As per the McDonalds website:
Water, Vegetable Oil (Soya Oil), Gherkins, Sugar, Spirit Vinegar, Modified Maize Starch, Free Range Egg Yolk, Mustard Seed, Salt, Acetic Acid, High-fructose Corn Syrup, Mustard Flour, Stabiliser (Xanthan Gum), Preservative (Potassium Sorbate), Natural Flavourings, Firming Agent (Calcium Chloride), Dried Garlic, Spice, Colour (Paprika Extract).

the sauce is secretely delicious...that is all you need to know. DONT QUESTION THINGS THAT ARE GOOD.