Re: [patch] ox-latex.el: Add `LATEX_PRE_HEADER' keyword

[Max Nikulin]

On 25/09/2023 01:42, Juan Manuel Macías wrote:
> According to the pdfx package documentation
> (https://www.ctan.org/pkg/pdfx), p. 6 (at the bottom of the page)/7:
> ---
> Warning: The \jobname.xmpdata file may be included in the main document
> source, within a {filecontents*} environment, provided this comes before
> the \documentclass command, as follows[...]
> ---

Does it mean that with hyperxmp you can not generate documents 
satisfying some requirements and you need namely pdfx? Is there a reason 
that .xmpdata files must be generated namely by a LaTeX engine and 
writing them by elisp code is unacceptable?

> For example, the newpax package, to preserve the internal links of a pdf
> included in the document, requires putting commands like
> \DocumentMetadata{ } before documentclass.

If I understand it correctly, \DocumentMetadata is a switch to enable 
"new" LaTeX like it was for \documentclass vs. \documentstyle during 
transition to LaTeX2e from LaTeX 2.09. If so, Org should have native 
support of \DocumentMetadata, not LATEX_PRE_HEADER or something similar. 
I have not looked into Timothy's branch, so I am unaware if it is addressed.