https://openjdk.java.net/ 
public interface jdk.nashorn.internal.ir.BreakableNode extends jdk.nashorn.internal.ir.LexicalContextNode, jdk.nashorn.internal.ir.JoinPredecessor, jdk.nashorn.internal.ir.Labels
  minor version: 0
  major version: 59
  flags: flags: (0x0601) ACC_PUBLIC, ACC_INTERFACE, ACC_ABSTRACT
  this_class: jdk.nashorn.internal.ir.BreakableNode
  super_class: java.lang.Object
{
  public abstract jdk.nashorn.internal.ir.Node ensureUniqueLabels(jdk.nashorn.internal.ir.LexicalContext);
    descriptor: (Ljdk/nashorn/internal/ir/LexicalContext;)Ljdk/nashorn/internal/ir/Node;
    flags: (0x0401) ACC_PUBLIC, ACC_ABSTRACT
    MethodParameters:
      Name  Flags
      lc    final

  public abstract boolean isBreakableWithoutLabel();
    descriptor: ()Z
    flags: (0x0401) ACC_PUBLIC, ACC_ABSTRACT

  public abstract jdk.nashorn.internal.codegen.Label getBreakLabel();
    descriptor: ()Ljdk/nashorn/internal/codegen/Label;
    flags: (0x0401) ACC_PUBLIC, ACC_ABSTRACT
}
SourceFile: "BreakableNode.java"