# File lib/selenium/webdriver/firefox/extension.rb, line 16
        def write_to(extensions_dir)
          root_dir = create_root
          ext_path = File.join extensions_dir, read_id_from_install_rdf(root_dir)

          FileUtils.rm_rf ext_path
          FileUtils.mkdir_p File.dirname(ext_path), :mode => 0700
          FileUtils.cp_r root_dir, ext_path

          FileReaper.reap(root_dir) if @should_reap_root
        end