These files define the following information required by the application launcher or system shell:
the application’s caption. This is often displayed beside the icon in the application launcher, and is usually the application’s name,
an optional short version of the caption. This is used by some UIs in situations where screen space is limited,
the name of the icon file,
for view-based applications, optional information about the views, including view-specific captions and icons. This feature may not be supported by all UIs.
an optional application group name. This may also be defined in the registration file. If it is defined in both files, the localisable version takes precedence.
This information is defined using a LOCALISABLE_APP_INFO resource struct, see AppInfo.rh. This resource can either be defined in a icon/caption definition resource file, or in the application's UI resource file, if it has one.
This choice of two methods is provided to give flexibility. For instance:
applications without any UI resources but which require icons/captions might need to use an icon/caption definition file,
applications with UI resources that do not need to be localised, but which require multiple captions, would use a single UI resource file, but several language-dependent icon/caption definition files,
for applications with localisable UI resources and different captions for different languages, it may be more convenient to define the caption/icon information in the UI resource files instead of using icon/caption definition files.
Localisable information is optional. A set of default icons are provided by the GUI, and the default caption is the application name.