You can do it in Settings -> Templates. Replace %FILE_ICON% in the listing/embedded template with something like:

Then drop xlsx.svg, docx.svg, pdf.svg etc into that folder.
Thread Starter
cabl
(@cabl)
Thanks for your instant reply!
It works quite well already with this:
<img loading="lazy" src="/wp-content/uploads/icons/%FILE_EXT%.svg" alt="" width="16" height="16"> <strong> <a href="%FILE_DOWNLOAD_URL%" target="_blank">%FILE_NAME%</a></strong> %FILE_DESCRIPTION% (%FILE_SIZE%)<br />
One small layout issue is that the icons are currently positioned too high. It would be nice to have something like the old align="bottom", so the icons remain bottom-aligned within the text following. 😉
Hmm you can add it in or add a css class and target it in your style css?