https://openjdk.java.net/ 
public interface jdk.nashorn.internal.ir.PropertyKey
  minor version: 0
  major version: 59
  flags: flags: (0x0601) ACC_PUBLIC, ACC_INTERFACE, ACC_ABSTRACT
  this_class: jdk.nashorn.internal.ir.PropertyKey
  super_class: java.lang.Object
{
  public abstract java.lang.String getPropertyName();
    descriptor: ()Ljava/lang/String;
    flags: (0x0401) ACC_PUBLIC, ACC_ABSTRACT
}
SourceFile: "PropertyKey.java"