Minecraft: Java Edition - Snapshot 20w21a

https://www.minecraft.net/en-us/article/minecraft-snapshot-20w21a 

• Added the ability to toggle redstone wire between a cross and a dot 

• Added import/export world settings functionality 

• Added disableMultiplayer and disableChat command line options • Added support for custom worlds and custom dimensions 

• Updated logos for Mojang Studios and Minecraft 

• Technical changes and bug fixes