From what I can tell, notes are stored in the DB, but can be exported as JSON, or I think markdown. It sure about markdown. I’ve only been able to export JSON, and it didn’t include the image I had embedded in the note. Whatever isn’t a note (images, movies, pdf, doc, etc.) is stored on the file system in a directory structure that files them under heap -> asset checksum. Thumbnails are included there if applicable. In that regard, it kind of forces you to use its folder structure.