Open Have this green thing in the map, what is it?

[Gabriel Meda]

http://prntscr.com/nnos7b i have seen this thing in the map, anyone now what this is? , i'm using " voide "
cobble generator preset.

 

[grandrolf]

Starter island?

Is this Skyfactory 3 on a server perhaps?

(or you're on SP and created a new island with the commands)