The normal.json file in the vanilla worldgen files uses "preset": "minecraft:overworld"

There is no way to know what this preset is, or edit it, even though it is multinoise, making it impossible to edit vanilla biome placement.

it was possible to edit vanilla biome placement in 1.18 by editing the overworld dimension file

vanilla worldgen:
https://github.com/slicedlime/examples/blob/master/vanilla_worldgen.zip