Thank you for reaching us. I believe we are seeing different things, probably because we are using different softwares to view the file. From our side, we have now white layer. All layers are how ever named (not sure if you can see that on your side) as:
Bauhaus Campus 2021 (these are the boundaries of the site where you should design). The site can be considered flat for the purposes of this excercise
Iconic Buildings (these are the Bauhaus building by Gropius, the hosues for the masters of the Bauhaus and the new Bauhaus Museum by addenda architects)
Hope this helps. If not, maybe you can send us a screenshot of the contour line that needs clarification.