[zulko]

I am thinking about it and there may be a way to do it using Pug mixins (like LaTeX macros).

Also, ReLaXed supports Markdown-it, which in turn has plug-ins for footnotes and citations, for instance. Not sure what you mean by auto-reference, but that should be possible, like in any other HTML page, wouldn't it ?

[Drdrdrq]

Not OP, but one of the most useful things about wkhtmltopdf is its ability to create an index page (edit: TOC) with references to all heading tags (<h1>,...). Is this something that can be done with ReLaXed?

[zulko]

Your PDF will automatically reference the h1, h2, etc, as sections and subsections in your PDF (i.e. you should see them in the sidebar's document tree in PDF viewers that have such a feature). You can also certainly generate a TOC using some javascript framework. For a quick google search I found this:

https://css-tricks.com/automatic-table-of-contents/