In Microsoft Windows, a resource is an identifiable, read-only chunk of data embedded in an executable file—specifically a PE file.
An application can be internationalized by associating the same identifier to resources that have the same content but localized for different languages.
Via Multilingual User Interface, Windows can be set up to use the resource for a selected language.
Editors are available that can modify resources embedded in EXE or DLL files.
These are typically used to translate all strings of an application to another language, or to modify its icons and bitmaps accordingly.