Classifications tend to be used in order to group several related products into one distinct entity.
The classifications layer is disabled by default; it can be turned on or off using the useclassification parameter, in the Bug Fields section of the edit parameters screen.
Access to the administration of classifications is controlled using the editclassifications system group, which defines a privilege for creating, destroying, and editing classifications.
When activated, classifications will introduce an additional step when filling bugs (dedicated to classification selection), and they will also appear in the advanced search form.