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