Yes, this is not related to phonegap, but interviewer expects the answer!

Property lists are a way of structuring arbitrary data and accessing it at run-time. An information property list is a specialized type of property list that contains configuration data for a bundle. The keys and values in the file describe the various behaviors and configuration options you want applied to your bundle. Xcode typically creates an information property list file for any bundle-based projects automatically and configures an initial set of keys and values with appropriate default values. You can edit the file to add any keys and values that are appropriate for your project or change the default values of existing keys.