Description
Helps fix missing mappings for blocks and items for removed mods.
Let's say you have two mods in your world, Silimatics and Refraction. Refraction adds Lasers, right? Now if one day you want to remove refraction, you wouldn't want all of those lasers to vanish, right? You might want to change them out automatically for Silimatics Glass! For that purpose Mapper exists. It also works with items.
A file called mapper.properties will be created. It is located in the same folder that contains the mods folder, i.e the folder with the resource packs, config, etc. folders. In it, just place your mappings like so (one per line):
refraction\:laser=smedry\:glass
Notice how I used "Smedry" and not "Silimatics". You need to make sure you use the actual resource location, which you can look up using F3+H in game. The backslash after the mod ID is to prevent Java from thinking you want to map "refraction" into "laser" :)