Happy to have support for importing citations from Google Books. It would be great if we could also “auto-download” books out of copyright. As best I can tell, this has not been implemented yet. (Though I import from Google Books with a PDF link on the page, Paperpile claims “No PDF Links Found.”)
The “Download PDF” link seems to be present in a country specific manner. It is displayed in the US, but no in European countries. We will check how to best deal with this situation and if we can extract the download link.