Altitudo

First release.

Altitudo is a world type that runs the Overworld from -2032 to 2031 and the Nether from -128 to 1023, with the generation following them down and up. Caves reach the new floor, ore keeps vanilla's density at every depth and gets richer below sea level, and the Nether's bedrock roof rises with its terrain instead of leaving a solid block of netherrack above the old one.

• A world type, not a switch. Pick Altitudo when you create a world; leave it and the world is exactly the vanilla one, in the same instance.
• Nothing under minecraft: is replaced. Existing worlds are untouched and other data packs keep working.
• Caves, aquifers and ore follow the floor — the deep is cave with water and lava in it rather than shapeless voids.
• Other mods' ores travel too, recognised by being configured as ore rather than by a list of ids. A mod can decline with the #altitudo:keep tag.
• The Nether's lava sea is 160 blocks deep instead of 32, and the roof keeps the 128 blocks of building space above it that vanilla leaves.
• Everything is derived from the config, so the depth is a value rather than one of a handful of prebuilt packs.

For NeoForge 21.1 on Minecraft 1.21.1.