I've been trying to migrate my 1.12 worldgen code over to 1.15. All the advice I have seen on similar topics is "look at how the vanilla source does it". (Swamp huts seem like a good example for my case)   Where exactly can I locate the vanilla source? I seem to recall for 1.12 there was a gradle task to decompile, but doesn't seem to be one for 1.15.