Hierarchical Knowledge Base file. This type of file uses a hierarchy of categories. Multiple levels of categories might be beneficial when similar concepts appear in more than one category. By grouping categories under a branch, it is easier to locate a specific solution associated with a category. The following code is a hierarchical knowledge base with two top-level categories: English and German. The knowledge base name is still KB, but now the five categories are repeated for each language.
<?xml version="1.0" encoding="UTF-8" ?>
<knowledge-base name="KB">
<category name="English">
<category name="apparel - English"/>
<category name="automotive - English"/>
<category name="baby - English"/>
<category name="beauty - English"/>
<category name="books - English"/>
</category>
<category name="German">
<category name="apparel - German"/>
<category name="automotive - German"/>
<category name="baby - German"/>
<category name="beauty - German"/>
<category name="books - German"/>
</category>
</category>
</knowledge-base>