A category whose feature settings are different from the settings of its parent category.
For example, suppose there is a branch of the category tree with 5 category levels (L1, L2, L3, L4, and L5). Suppose the feature settings for SiteDefaults, L1, L4, and L5 are all "A", and the settings for L2 and L3 are "B". In this case:
L1's settings (A) match the site default, so L1 is not returned.
L2's settings (B) are different from L1's, so L2 is returned.
L3's settings (B) are the same as L2's, so L3 is not returned
L4's settings (A) are different from L3's, so L4 is returned
L5's settings (A) are the same as L4's, so L5 is not returned.
If you specified a particular FeatureID in the request, this field only returns feature settings for that feature. Only returned when the category is different from its parent. If the category has children and they aren't returned, it means the children inherit the category's feature settings.