I a tool in place to export this data to help power the experimental RSS preview feature[1], but haven't had the inspiration to do much with that yet.
[1] e.g. https://search.marginalia.nu/site/jvns.ca
--edit-- Ok so there was interest. Give me a moment, I'll need to run an extraction script. Check back in a few hours or bookmark https://downloads.marginalia.nu/exports/