When you view a product, you view it in the context of a sandbox. This means that you are viewing the product's settings as it exists as a deployed product, plus any undeployed changes made to the product in that sandbox.
If a product has changes in it in that sandbox, the plan name will be yellow and there will be a pencil icon next to the product name, like this: 
On a product's detail page, any fields that have been changed from the deployed version will be outlined in the color of the sandbox.