Comment by Mikhail_Edoshin

The stylistic includes and certain content (e. g. a site map) can be embedded in the XSLT itself.

It is not quite a templating engine. XSLT is a part of a semantic engine. Content is written in the way that fits the content. E. g. I write about some language and invent tags and notations that best fit what I am talking about: grammar, sounds, wrtiting. Or I write about chess and say something like (party id=abc move=15w). Then I make it available in HTML by providing a transform from my tags to HTML tags. My notation is rendered as a bunch of divs, ps and spans. This is merely a temporary rendering; other renderings may be possible.

A templating engine is the final document with placeholders for variable parts. XSLT can do that too, but this is less than its vision.