code: private void popTag()
      {
          Stack<UIComponentClassicTagBase> stack = getStack(pageContext);
  
          int size = stack.size();
          stack.remove(size - 1);
          if (size <= 1)
          {
              pageContext.removeAttribute(COMPONENT_STACK_ATTR, PageContext.REQUEST_SCOPE);
          }
  
      }
docs: The pageContext's request scope map is used to hold a stack of JSP tag objects seen so far, so that a new tag can
  find the parent tag that encloses it. Access to the parent tag is used to find the parent UIComponent for the
  component associated with this tag plus some other uses.