Notebooks’ system files (plist files) ensure that all books and documents appear identical on all devices. The files include metadata like selected font and document style, color label, custom sort order, assigned tags and much more. Notebooks never shows them, but when synced to your computer these files show up in Finder or in Windows Explorer.
If you don’t want to see these files on your hard drive, and if you do not mind that your books and documents may look different on each device, you can turn off “Sync System Files” in Notebooks’ sync settings, and Notebooks will no longer export them. – A few essential files like those for Notebooks’ task lists will be exported anyway.
Can I Turn Off “Sync System Files”? – I do not mind my files looking different on all devices