Mac OS X Panther in a Nutshell, 2nd Edition

The Info.plist File

Metainformation about your project, which you usually define through Xcode’s Project→Edit Active Target (Option--E) dialog, is stored in a special Info.plist file, which Xcode writes to the application’s /Contents folder upon building. Every Bundle-style application on your system (that is, every Cocoa application and every Bundle-style Carbon or Java application as well) has one of these files, which are, like all .plist files, in Property List XML format (described in Chapter 25).

Taken together, all the /Applications/ AppName .app/Contents/Info.plist files installed in all the filesystem’s domain-level Applications folders compose a registry of all applications available to the machine. This lets the system build a database of application information, which lets the Finder assign the correct Kind to application-specific files under its List view and Info windows, the defaults program pair preference domains to applications (see Chapter 25), and more. The application itself can also pull information from this file to help build its About dialog, for example, as well as to find out what file format its own documents use.

A related file, version.plist, can exist in the same directory as Info.plist . As its name suggests, it contains information about the applications’ version and build numbers, as well as release status.