code: function Tag(el, opts) {
        // get the tag properties from the class constructor
        var ref = this;
        var name = ref.name;
        var tmpl = ref.tmpl;
        var css = ref.css;
        var attrs = ref.attrs;
        var onCreate = ref.onCreate;
        // register a new tag and cache the class prototype
        if (!__TAG_IMPL[name]) {
          tag(name, tmpl, css, attrs, onCreate);
          // cache the class constructor
          __TAG_IMPL[name].class = this.constructor;
        }
  
        // mount the tag using the class instance
        mount$1(el, name, opts, this);
        // inject the component css
        if (css) { styleManager.inject(); }
  
        return this
      }
docs: Another way to create a riot tag a bit more es6 friendly
  @param { HTMLElement } el - tag DOM selector or DOM node/s
  @param { Object } opts - tag logic
  @returns { Tag } new riot tag instance