I posted a question on stackoverflow for it already but so far no answer there either:
Any advice? Since I posted the stackoverflow question I noticed the activeColumns on the mockup structure pattern, so, maybe I have to compile my own version of mockup?
Since resource registry settings are saved in the (registry.xml), you can export the Export the configuration registry schemata step via ZMI - portal_setup - export, this will show you the full registry.xml. Something like this will be inside for the pattern options:
Just to clarify: folder_contents and tabular_view are two completely different things.
The folder_contents aka Contents at the top left in the toolbar uses the pat-structure pattern with pattern options which soon can be configured again in the controlpanel.
tabular_view is the folder and collection template which you can select in the Display action and right now you can configure columns in the collection schema but this is pretty old code. It might be more useful if there would be a layout behavior and a controlpanel where you can configure globally and per context basis the look and feel of your tabular folder listing.
I did something similar in an addon for folderish types: collective.gridlisting. Plone >= 6 only.