Terrace outside the buildable plot area - allowed?

The footprint of these structures is only to be counted half towards the permissible footprints as well as the permissible exceedances for ancillary structures

Then I consider a permit to be necessary. The question that still arises for me is whether the builder will construct the terrace immediately or if it will be realized later by the owner. If it is built right away by the builder, the semi-detached house partner also has such a terrace and therefore I see the likelihood as low that anyone would object to it.

For me personally, it would be unsatisfactory to have something unapproved on my property, but judging by what I see in my building area, I am probably the exception with this point of view.

The outdoor facilities are not part of the BT service. That's why I ask. The neighbor will probably not have anything against it...

Regarding 1. No, there is nothing mentioned about terraces.

This is regulated in the state building code, and in the development plan only if there are exceptions.

I inquired with the BT today - the drawing from which I posted the excerpt is part of the building permit. We have now signed the reservation...

Drawing from which I posted the excerpt is part of the building permit

That sounds good, but in my opinion it is useless in case of doubt if no application for deviation from the development plan has been submitted and approved (separate form for the building application). The building boundary was set in the development plan and may therefore only be exceeded by an approved deviation.

Of course, this is not a problem in most cases, since such things are - as a rule - only checked on a case-by-case basis.