https://openjdk.java.net/ 
public interface jdk.nashorn.internal.runtime.regexp.joni.constants.StackPopLevel
  minor version: 0
  major version: 59
  flags: flags: (0x0601) ACC_PUBLIC, ACC_INTERFACE, ACC_ABSTRACT
  this_class: jdk.nashorn.internal.runtime.regexp.joni.constants.StackPopLevel
  super_class: java.lang.Object
{
  public static final int FREE;
    descriptor: I
    flags: (0x0019) ACC_PUBLIC, ACC_STATIC, ACC_FINAL
    ConstantValue: 0

  public static final int MEM_START;
    descriptor: I
    flags: (0x0019) ACC_PUBLIC, ACC_STATIC, ACC_FINAL
    ConstantValue: 1

  public static final int ALL;
    descriptor: I
    flags: (0x0019) ACC_PUBLIC, ACC_STATIC, ACC_FINAL
    ConstantValue: 2
}
SourceFile: "StackPopLevel.java"