The singularity going up on south produced some REAL INTERESTING landscaping art, which looked like this:

(:[])

In other words, a round mound with rectangular holes, inside a crater.

Do some death explosions except dirtbag have negative cratering now?

That explains the square holes, and i'm used to those. They also look nice as the last traces of vanished civ, such romantic ruins.

But the mound? that semispherical feature rising back from the crater?

All craters in Spring have a shape like this:

..._............_...
/..\........../..\
.......\......./......
........\__/.......

They are usually quite flat so it is not clearly visible.