Peanuts may contain traces of peanuts

My question after reading the label of a packet of peanuts was; if it only contains TRACES of peanuts, what is the rest?

Yummy Snack Foods 500g peanuts
Yummy Snack Foods 500 gram salted peanuts
Peanuts may contain traces of peanuts
Peanuts may contain traces of peanuts. So what else do they contain?

Are peanuts nuts?

Well it looks like peanuts are not officially nuts. Reading Wikipedia about them they are classified as Arachis hypogaea, a legume crop grown mainly for its edible seeds. As a legume, the peanut belongs to the botanical family Fabaceae; this is also known as Leguminosae, and commonly known as the bean, or pea, family. So I suppose the statement is partially relevant, may contain traces of … other nuts.

The Wikipedia article does go onto to say further down:

Some people (0.6% of the United States population) report that they experience allergic reactions to peanut exposure; symptoms are specifically severe for this nut, and can range from watery eyes to anaphylactic shock, which is generally fatal if untreated. Eating a small amount of peanut can cause a reaction. Because of their widespread use in prepared and packaged foods, the avoidance of peanuts can be difficult. The reading of ingredients and warnings on product packaging is necessary to avoid this allergen.

Link to the Wikipedia article referred to is https://en.wikipedia.org/wiki/Peanut