So I noticed that when I enter a book by ISBN, I get one entry as expected. If I have a book with a different printing and published date is that not in core? When you submit changes to core, it shows the fields to change, are these all the possible fields that are in core?
What is your exact question here?
Which fields we have in Core for books? (that is not something we share, but if I understand what you really want to know or do, maybe I can help).
Please note that submitting to Core is optional, and if it’s a hassle or difficult, just don’t do it. No worries. Make sure YOUR database is as good as you want it to be for you!