DITA 1.3 includes the possibility of using a concept called Key Scopes (or scoped keys). It allows you to reuse a topic in multiple places within the same DITA map, but with slightly different content in each instance.
Suppose that you develop a software product and you have a topic in your user guide that explains how to install your product on a Windows operating system. Suppose that the steps are exactly the same for installing it on Linux and the only difference is the name of the operating system. Therefore, it would be helpful if you could reuse the exact same content in two different topics, but with the name of the operating system different in each instance. In DITA 1.2, this is not possible since keys can only be resolved to a single value. However, with the DITA 1.3 Key Scopes mechanism, you can define multiple values for the same key depending on the context.
Edit properties.Save the DITA map.
Result: In the DITA Maps Manager, you can now see the key scopes in brackets and when you open each topic reference.
The content will also be expanded in Author mode according to the context of the key scope you defined for that particular topic. Also, when you transform the DITA map, the scoped keys will be reflected in the published content.
For more information about key scopes and other advanced DITA reuse concepts, watch our Webinar: Working with DITA in Oxygen - Advanced Profiling and Reuse Strategies.