<iframe>, <object>, and <embed> all work. But you need to add target="_parent" or target="_top" to all links. There really should be an <include> element. e.g.

<iframe>, <object>, and <embed> all work. But you need to add target="_parent" or target="_top" to all links. There really should be an <include> element. e.g. https://www.w3.org/TR/xinclude-11/ https://www.w3.org/TR/xinclude-11/