This tool allows you to toggle the flags that the game uses to track your discoveries of map features. For example, you can make the game think that you have discovered magma so that you can build magma workshops and furnaces. You can also toggle the cavern layer discovery flags so you can control whether trees, shrubs, and grass from the various cavern layers grow within your fortress.
List all map features in your current embark by index.
Enable magma furnaces (discovers a random magma feature).
feature show <index>
Marks the indicated map feature as discovered.
feature hide <index>
Marks the selected map feature as undiscovered.
There will usually be multiple features with the
type. These are the cavern layers, and they are listed in order from closest to
the surface to closest to the underworld.