XML标准不允许在xml文档中添加多个根元素.因此，我认为在XML标准不允许的情况下，任何与XML兼容的应用程序都不会支持多个根元素.

XML standard does not allow to add multiple root elements in xml document. So I do not think that any app which works with XML will support multiple root elements when it is not allowed by XML standard.