I thought the same about the secondary ranking, but sometimes it’s strange.
Fortunately, the people at the building authority are super friendly and explain everything.
Another point, which is not really up for debate now but just occurred to me: Sometimes such entries in the land register could also be to the detriment of the owners. Imagine you want to sell your property. A prospective buyer looks at the land register and sees "garden land". Naturally, they will try to negotiate the price for the garden land. Of course, they might encounter "deaf ears" on the seller’s side, but this could just as well cause potential buyers to slip through their fingers. Well, be that as it may, it’s a rather confusing detail that should definitely be questioned or checked carefully.
Thanks for your answers!