@Kiwidude when using the new Grid display associated with the new backend Kovid indicates marked books with a big star overlay. I noticed every time I restarted calibre I had 19 books marked (
see this thread.) It turns out they are Duplicate exemptions from this plugin. In the list view I never noticed them pre-marked. I cleared the exemptions and they are no longer marked. I just thought I would tell you in the new DB these exemptions are brightly flagged for all to see.