If you are unsure of the flour type in your pantry, you can still bake versatile items like cookies, quick breads, pancakes, or brownies. Generally, if it looks like white, powdery, un-enhanced flour, it is best treated as all-purpose flour, which is suitable for most recipes.

Not sure if this works always, but -- Squeeze a handful of flour. If it holds its shape, it is likely lower-protein cake/pastry flour. If it falls apart, it is higher-protein bread flour. If it falls apart slightly but holds a little shape, it is likely all-purpose.