https://openjdk.java.net/ 
public interface org.w3c.dom.css.CSSUnknownRule extends org.w3c.dom.css.CSSRule
  minor version: 0
  major version: 59
  flags: flags: (0x0601) ACC_PUBLIC, ACC_INTERFACE, ACC_ABSTRACT
  this_class: org.w3c.dom.css.CSSUnknownRule
  super_class: java.lang.Object
{
}
SourceFile: "CSSUnknownRule.java"