Acid regulating agent 6 is a food additive. Below are all the products whose label lists it, ordered just like the other lists.
Acid regulating agent 6 (E330) – acidity regulator. Citric acid occurs naturally in citrus fruit; used for a tangy taste and as a preservative.
Source: EU register of food additives (Reg. (EC) No 1333/2008) and EFSA.