How do products have ‘secret recipes’ if they need to disclose the contents on the packaging?

Question

How do products have ‘secret recipes’ if they need to disclose the contents on the packaging?

In:

Answer 1

They don’t have to disclose the amounts of each ingredient, often those that make the most difference are listed as “natural flavors” or “spices”, and they don’t list anything about techniques used in the recipe (mixing/cooking, etc. methods and such)