I accidentally deleted the group that displays various keywords in bibdesk.
It should look like this: https://i.stack.imgur.com/bS1d4.jpg
I found this documentation entry that explains field groups: https://bibdesk.sourceforge.io/manual/BibDeskHelp_33.html
So: How can I set up this group by keywords manually?
I have reinstalled bibdesk, but the issue remains.