This data pack increases the World height of the over-world to 1024 blocks.
It now ranges from y = -64 to y = 1023.

The end and the nether are unaffected.

This is compatible with world edit. But there are lag spikes, when you use it to change unloaded chunks (for example, when you build a 1000 block tall dirt tower; The chunks far above you are unloaded).

This might impact performance.
This changes world generation.
The Biomes and structures generate in the same way and height, but at different places. Biomes now generate normally.
This data pack also works in super flat worlds. This data pack does not work on single Biome worlds (it does increase the world height, but breaks world generation).
Please backup your world before trying this.
The /locate and /locatebiome commands still work.

This is nothing new. This data pack just has the 1.18 world Generation, while the old ones were made for snapshots before the release of 1.17.