The aim is to declare a zone as inherited from another zone, so when the current zone is empty it will inherit the content of the named zone in the parent page.

e.g. A skin with a single template with a zone 'default' and a zone 'right'. By declaring the 'right' zone as inheriting the 'right' zone, the following behavior will apply : when the right zone is empty, it is filled with the content of the right zone in the parent page (or the parent-parent page...).