Hans van der Meer schrieb am 04.03.2020 um 13:23:
On 3 Mar 2020, at 22:04, Rik Kabel <context@rik.users.panix.com> wrote:

Instructions for creating the .epub from the export are contained in the log file.

In the log comes:
    create epub with: mtxrun --script epub --make "kookboek" --purge --rename --svgmath
This I did.

The log gives:
 adding: mimetype (stored 0%)
  adding: META-INF/ (stored 0%)
  adding: META-INF/container.xml (deflated 32%)
  adding: OEBPS/ (stored 0%)
  adding: OEBPS/nav.xhtml (deflated 49%)
  adding: OEBPS/images/ (stored 0%)
  adding: OEBPS/kookboek.opf (deflated 65%)
  adding: OEBPS/styles/ (stored 0%)
  adding: OEBPS/styles/kookboek-styles.css (deflated 35%)
  adding: OEBPS/styles/kookboek-defaults.css (deflated 80%)
  adding: OEBPS/styles/kookboek-images.css (deflated 7%)
  adding: OEBPS/cover.xhtml (deflated 38%)
  adding: OEBPS/kookboek-div.html (deflated 67%)
  adding: OEBPS/toc.ncx (deflated 53%)
mtx-epub        | epub archive made using zip: kookboek.epub


But, the resulting epub is bad. Compare the output as pdf with the output as epub and it is immediately clear that something is wrong in the production of the epub. See also the corresponding -raw.xml. Unless I am making a gross mistake.

You make things easier when you show your TeX file.

Wolfgang