I think the "Enable special fields" should move to another preference tab as this is not really related to the main table. Moreover, is the "Show extra columns" still needed (and what does it do)? Any maybe rename "Natbib style" to what it actually represents (which is actually not clear to me...).

'Show extra columns' adds additional columns to the combobox providing a column for every filetype (instead of one column displaying different icons for each filetype). In refactoring the tabs to the mvvm pattern we discussed removal of these columns, but decided to keep them, as they were not really complicated to implement or maintain. We didn't want to kill a feature (even though there is probably hardly a use case) without need.

About special fields: I did not yet have any better idea to place them but the general tab. But this is no permanent solution. So I decided to keep this as it is and leave it to a dedicated SpecialFields PR, because I would like to focus here on extracting the calls to JabRefPreferences out of the codebase.

NatBib style is (if i remember right) 'Lastname' or 'Lastname et al.'

Done what I planned to do here.
@tobiasdiez do you have a suggestion for the natbib label?

What about "Show only lastname" instead of natbib? (but this is already in abbreviations...so I'm not sure what natbib actually does ;-)).

Ok, then I would vote to remove the "Show extra columns" option and always add these fields to the dropdown. It's not hurting if there are a couple of more options to select.

I agree with the special fields, it was just an observation as you were already touching the code.

I'll review the code later....

I fear a merge conflict in/with #6479 regarding the maintableformatter. Therefore I would propose to first merge the other PR and then this.

Agreed. I took a look at it, we definitely should merge #6479 first. Integrating the changes shouldn't be that hard. Although we worked on the same code, we were working on different aspects.

#6479 has been merged now.