I have a package of dried prunes with a Rav Machpud hechsher, which says it’s only for those who eat kitniyos. Wis in dried prunes that it would be considered kitniyos?
Nowadays there are alot of things that go on with the food that we eat that we are not aware of, and there are a lot of chemical, preservatives, etc. being added to our simple looking foods. Therefore many seemingly innocent foods nowadays will need kosher for Passover supervision. The reason why dried fruits need to be kosher for Passover is because dried fruit producers will often use rice or oat flour or chemical release agents to coat their cut up fruit pieces to prevent sticking, or potassium sorbate to help the moisture of the fruits, which can be derived from grains.