https://github.com/JetBrains/java-annotations: A set of annotations used for code inspection support and code documentation. 
public interface org.jetbrains.annotations.Unmodifiable extends java.lang.annotation.Annotation
  minor version: 0
  major version: 59
  flags: flags: (0x2601) ACC_PUBLIC, ACC_INTERFACE, ACC_ABSTRACT, ACC_ANNOTATION
  this_class: org.jetbrains.annotations.Unmodifiable
  super_class: java.lang.Object
{
}
SourceFile: "Unmodifiable.java"
    RuntimeVisibleAnnotations: 
      java.lang.annotation.Documented()
      java.lang.annotation.Retention(value = java.lang.annotation.RetentionPolicy.CLASS:Ljava/lang/annotation/RetentionPolicy;)
      java.lang.annotation.Target(value = {java.lang.annotation.ElementType.TYPE_USE:Ljava/lang/annotation/ElementType;})