[Request] World Downloader Feature for 1.12.2

[JusturGamer]

I would like to Download Worlds (Servers, Realms ect.) To my hard disk for later playing or for a backup and I really would love to just need to install impact for this.

[garrisonguy]

Impact works on almost all types of worlds but.....i made a world in optifine then i switched to impact. played for a while and then switched back again to optifine. now my world is gone ffs.

[wellsilver]

I would also like a world downloader