It does a variety of changes to the nether, biome distribution remains the same.
Changes:
Higher nether generation up to 224
The top 32 layers are netherrack with small caves, so is more like 192, and is not everywhere but when it happens it will be more open
Why this?
256 height takes away from the lava ocean which is a key part
of the nether level design but I do want the nether taller
The carvers don't go down bellow the lava ocean
Why this?
Simply because an impossible to cross lava barrier is neither
fun or adds depth, is just a stop sign
Higher amount of quartz
Why this?
The demand for quartz can be high for building and quartz is a
common source of experience for players
Ancient debris generates more scattered
Spawns mostly in single blocks but is more common to stumble to
Why this?
Reduces the chances of rng playing with you, by having higher
odds of hitting netherite even if smaller amounts it makes the
progress towards getting the netherite be less aimless
Unhardcoded the basalt delta columns
This is mostly a technical thing, but I just recreated the columns in a way which isn't as harcoded as vanilla does it
Why this?
It is more structure friendly.