This script allows you to create “placeholder maps”, which are maps that are meant to be replaced with other maps when you load the map. It uses something called a “replace map formula”, which is just a regular ruby formula.
When you load a map such as transferring from one map to another, the engine first determines whether a different map should be loaded or not.
The intention behind this script is to allow you to easily change a map’s visuals (while keeping all transfer points basically the same) without having to find a way to set up your transfer events to check conditions to determine which map to go.
For example, suppose you have a castle town map, and later on in the story, the castle town is destroyed. Two maps are used to achieve this: one is the original castle town, the other is the ruins map. Your castle town may have a number of transfer points within the town leading to building interiors,
or to other maps in your world. This means that you will likely have a number of other transfer events that lead to the castle town.
If all you want to do is change the way your castle town looks from the original to your ruined version while keeping all of the transfer points the same, you can simply write a replace map formula to load the appropriate map.