Currently in the game is that many times you have to mine out chunks into mountains and/or cliffs so you could get materials like, ore, stone and clay.
When doing so, you may mis-click, accidently mine something you didn’t intend for, or want to refill and area. When the game resumes, your Hearthlings will dig out that area and leave a little hole.
The problem is, is that you cannot add stone, dirt, clay, etc. back, meaning if you accidently made a little hole near your base, it’s stuck there forever. Theres nothing you can do about it. To be quite honest, it makes me really frustrated. Usually I go back to a previous save and redo everything up until that point, trying not to make the same mistake.
The suggestion is that you can use stone, clay, and potentially dirt to (re)build any previous areas or mistakes, and you can even use it to make new mountains or hills out of stone or dirt.
It’s not very major, and I think it’ll be a nice little feature for people as they can make mountains around their base or to even encapsulate previous building or settlements.