@suzanne.soy: Thank you again for the functionality already implemented.

I apologize because I was unable before, to follow up and review the last changes.

I make the test, with (use-external-katex...) but it didn’t work as expected: For the moment I’m doing the change manually. That is: in the generated .html file of the .scrbl source, I change: href="<my-katex-folder>/katex/katex-min.css", and scr="<my-katex-folder>/katex/katex-min.js". Where <my-katex-folder>/ is the prefix that I add in the .html file, replacing <my-katex-folder> with the required folder. This solution works fine, for the moment, and save me the need to create an extra copy (each time) of the katex folder and its content.

Thank you in advance for any further observation or suggestion. Please Keep Safe. Best regards.