javadoc's PREVIEW page gives a detailed list of the preview API elements in a release: https://docs.oracle.com/en/java/javase/18/docs/api/preview-list.html

It would be helpful if this page listed the preview language features and preview VM features in the release, linking to their JEPs.

It might also make sense to list the names of preview APIs in the release -- such as "Foreign Function & Memory API" and "Virtual Threads" -- before showing the complete list of assorted preview API elements.