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

[Max Nikulin]

On 28/09/2023 19:31, Juan Manuel Macías wrote:
> Starting with \documentclass, the order is important in certain cases
> and not so important in others. And, anyway, you can always use a hook
> like \AtBegin... \AtEnd..., etc.

I am judging from my past experience. Besides \usepackage{cmap} that was 
necessary to be put immediately after \documentclass, there were issues 
with order of \usepackage for hyperref and some other packages.

Custom commands may require some attention as well. There is an example 
of reusing year in .xmpdata and document title in the pdfx docs. Such 
cases may be more subtle. In the case of .xmpdata command must be 
defined at the moment when the file is loaded, so it is not important 
either command definition or \begin{filecontents*} placed first 
(.xmpdata may be provided directly as well). In the case of 
\DocumentMetadata it is not obvious if commands may defined later.