feature Namespace
Optional feature namespace.
Namespace represents the feature namespace defined by the Selector within a featureset to which this feature belongs. If the underlying source is the same for multiple selectors within a featureset, the same featureNamespace should be used across those selectors. Defining a featureNamespace value for the Selector is recommended, especially when multiple selectors exist in a featureset, as it can enhance the efficiency of feature operations.