Copper Extension is a simple Minecraft Mod witch adds a few features to the copper set...
The major feature is the rusty copper ingots. Copper ingots can now be oxidixed in the inventory or even when you dropped it. And also they can be waxed using beehives or honeycombs.
Copper Extension is available on Forge and Fabric*(soon)* for version 1.20.1 and further on Curseforge and Modrinth