Didn't know that, had to look into it immediately! Looks like a lot of the stuff in the Notes sqlite file is encrypted, though. Will need to look into this some more, would be nice to make a nice little exporter.
Last I checked it was not encrypted (unless you explicitly asked it to encrypt a note). Just gzipped protobuf data. I wrote an extractor about six years ago, maybe it'll help:
It seems to still work for text. It looks like it doesn't dump tables anymore, so that bit may have changed (it was pretty convoluted). I think the extraction of drawing information doesn't work anymore, but they provide a fallback PNG file.
I wanted it to be self-contained, so it has a little hand-rolled protobuf decoder and might be a little code-golfy.
