Add attribute to settings-tab for a whole form in Umbraco Forms version 11.1.0

[emmjoh01]

We've got a problem when trying to add a custom setting-attribute in the settings for a whole form and we can't find any documentation for it or any way to solve this ourselves. We have seen at least one other person who has asked about this earlier but who has been told to check the documentation for adding a fieldtype where you can add a setting-attribute to the fieldtype but that's not what we want to do, we want to add a setting-attribute to a whole form so that it is possible to change the setting via the settings-tab in the upper right corner when you are standing on a form. I hope that the screenshots I paste in can help to show what I'm trying to explain.

On this page we want to add a dropdown where you can choose between a couple different things for the form but we haven't been able to do it.