They are old and worn roof tiles. Since the tiles are on the rooftop, it is full of lichen and bird poop.

With the SBSAR file, the amount of tiles, lichen, bird poop, dirty level, damage level can be manipulated.

It is a rock having a lot of moss and lichen on the surface. If you are going to create a natural environment, this material is fit for texturing large rocks, ground and cliff.