Changes for normal players

• Added cave biomes.
• River biomes no longer appear in oceans.
• Axolotls now spawn in underground pockets. Due to vanilla logic, they only spawn when clay is below them. Not all underground pockets will have clay in them.
• Molten rock in the core no longer spawns randomly. Instead, it's a smoother gradient.
• Fixed saplings failing to grow outside of big globe worlds.
• Fixed a lot of blocks not breaking quickly with the proper tool.
• Fixed a few blocks dropping the wrong items.
• Fixed bees not spawning in beehives in 1.20.5 and later.

Changes for data pack makers

• Layers (the chunk generator kind, not the rock layer kind) have been split up into separate files. They are no longer in the world preset.
  • This makes it easier to tweak them, but also means any data pack which already did this will need to update.
• Added a "noop"-typed layer, which does nothing, and does not have any configurable properties.
  • This layer type is intended for when you want to remove a layer with a data pack.
• The molten_rock configured feature type has been removed.
• Added new mechanism for data packs to add mob spawns to the world without replacing biomes.
• Added new weighted random switch statement for scripts.

• Added pale garden biome to the nether (MC 1.21.4 only).
• Added abandoned cities to the overworld.
• Fixed strongholds sometimes spawning in the deep dark.
• Spiders are now more likely to spawn in mineshafts and surface mineshafts.
• Endermen are now more likely to spawn in strongholds.
• Split up "data pack debugging" config option into multiple sub-options that show different information.

• Ported to MC 1.21.4.
  • The pale garden biome is NOT implemented yet.
• Fixed occasional script error being shown in the chat menu and log file.
• Possibly fixed some data packs failing to load correctly.