We've found some websites that have CDATA sections. One of them is https://www.tiens-donc.com/. I think @SantosGuillamot has more.

We need to decide what to do with those nodes. Maybe the first thing to investigate is what does Preact with them. Does it delete them? (as it does with the HTML comments)

I'm just opening the issue, so this is documented, but happy to see someone else take over on this 🙂