+ */
+
+/**
+ * \defgroup Validators Validators
+ *
+ * \brief Implementation of internal logic of the feature
+ *
+ * Validators are used for checking validity of the feature: each argument,
+ * dependencies between the arguments. Validators are defined in the
+ * configuration files and may be also used for selection filters (ModuleBase_SelectionValidator),
+ * passing configurable parameters from XML file to the feature implementation
+ * (like in ExchangePlugin_ImportFormatValidator).
+ *
+ */
+