https://developers.google.com/protocol-buffers/protobuf-java/: Core Protocol Buffers library. Protocol Buffers are a way of encoding structured data in an efficient yet extensible format. 
public interface com.google.protobuf.Descriptors$FileDescriptor$InternalDescriptorAssigner
  minor version: 0
  major version: 59
  flags: flags: (0x0601) ACC_PUBLIC, ACC_INTERFACE, ACC_ABSTRACT
  this_class: com.google.protobuf.Descriptors$FileDescriptor$InternalDescriptorAssigner
  super_class: java.lang.Object
{
  public abstract com.google.protobuf.ExtensionRegistry assignDescriptors(com.google.protobuf.Descriptors$FileDescriptor);
    descriptor: (Lcom/google/protobuf/Descriptors$FileDescriptor;)Lcom/google/protobuf/ExtensionRegistry;
    flags: (0x0401) ACC_PUBLIC, ACC_ABSTRACT
    MethodParameters:
      Name  Flags
      root  
}
SourceFile: "Descriptors.java"
NestHost: com.google.protobuf.Descriptors
InnerClasses:
  public final FileDescriptor = com.google.protobuf.Descriptors$FileDescriptor of com.google.protobuf.Descriptors
  public abstract InternalDescriptorAssigner = com.google.protobuf.Descriptors$FileDescriptor$InternalDescriptorAssigner of com.google.protobuf.Descriptors$FileDescriptor
    RuntimeVisibleAnnotations: 
      java.lang.Deprecated()