*
* @param <T> Mutation Type
*/
-// FIXME: sealed to allow Mutable and Immutable only when we have JDK17+
-// FIXME: consider hiding this interface afterwards
-public interface MutationBehaviour<T extends MutationBehaviour<T>> {
+sealed interface MutationBehaviour<T extends MutationBehaviour<T>> permits Immutable, Mutable {
// Marker interface only
}