Improve decoration documentation

API.md

@@ -254,8 +254,24 @@ The decorations are defined as follows:
     -- Y offset of the schematic base node layer relative to the 'place_on'
     -- node.
     -- Can be positive or negative. Default is 0.
-    -- Effect is inverted for decorations on the ceiling.
+    -- Effect is NOT inverted for decorations on the ceiling.
     -- Ignored by 'y_min' and 'y_max' checks, which always refer to the
     -- 'place_on' node.
 }
 ```
+
+## Ores
+
+This mod does not support adding ores to the caves, as this is a feature that
+is already well-supported by the Minetest Lua API and doesn't need a mod like
+this.
+
+## Misc
+
+In case you wish to do a few other operations, here's a few other functions
+that might be helpful to you:
+
+- `noordstar_caves.set_world_height(h)` Set the world's height to a given number.
+
+This feature is currently only supported in VoxeLibre. Contributions that help
+change the world depth in other games, are very welcome.