A property list, often referred to as a plist, represents a hierarchy of objects that can be stored in the file system (in key and value form) and reconstituted later. They consist only of certain types of data: dictionaries, arrays, strings, numbers (integer and float), dates, binary data, and Boolean values. Property lists give apps a lightweight and portable way to store small amounts of data.
Property lists in Xcode projects are contained in files with the .plist extension.
Click a property list in the Project navigator and the property list editor appears in the source editor pane, allowing you to inspect or edit its contents.