https://www.graalvm.org/ 
public interface com.oracle.truffle.tck.tests.ValueAssert$NonFunctionalInterface
  minor version: 0
  major version: 59
  flags: flags: (0x0601) ACC_PUBLIC, ACC_INTERFACE, ACC_ABSTRACT
  this_class: com.oracle.truffle.tck.tests.ValueAssert$NonFunctionalInterface
  super_class: java.lang.Object
{
  public abstract void foobarbaz();
    descriptor: ()V
    flags: (0x0401) ACC_PUBLIC, ACC_ABSTRACT

  public abstract void oldmacdonaldhadafarm();
    descriptor: ()V
    flags: (0x0401) ACC_PUBLIC, ACC_ABSTRACT
}
SourceFile: "ValueAssert.java"
NestHost: com.oracle.truffle.tck.tests.ValueAssert
InnerClasses:
  public abstract NonFunctionalInterface = com.oracle.truffle.tck.tests.ValueAssert$NonFunctionalInterface of com.oracle.truffle.tck.tests.ValueAssert
  public abstract Implementable = org.graalvm.polyglot.HostAccess$Implementable of org.graalvm.polyglot.HostAccess
    RuntimeVisibleAnnotations: 
      org.graalvm.polyglot.HostAccess$Implementable()