<% Layout.shareable %>
render the property "shareable" either as editor (checkbox) or as plain text (editor-mode works only for root-layouts)

Sourcecode in Layout/macros.js:
1:   function shareable_macro(param) {
2:      if (param.as == "editor" && !this.site) {
3:         var inputParam = this.createCheckBoxParam("shareable", param);
4:         if (req.data.save && !req.data.shareable)
5:            delete inputParam.checked;
6:         Html.checkBox(inputParam);
7:      } else if (this.shareable)
8:         res.write(param.yes ? param.yes : getMessage("generic.yes"));
9:      else
10:        res.write(param.no ? param.no : getMessage("generic.no"));
11:     return;
12:  }