Java Edition 1.18 experimental snapshot 2

1.18 experimental snapshot 2 [sic] is the second experimental snapshot for Java Edition 1.18, released on July 20, 2021, which makes numerous changes to world generation and mob spawning functionality related to spawners.

General

 * Tags
 * Spawners now have a new "CustomSpawnRules" tag, which lets players override the spawn rules of the spawned mob.
 * In the tag, players can specify "BlockLightLimit", which indicates the highest block-light the spawners will spawn mobs at.

Mobs

 * General
 * Zombie, skeleton, spider, and cave spider spawners now spawn mobs up to block-light level 11.

World generation

 * Beaches
 * Beaches are generally wider.
 * In some places there is a chance where no beaches generate at all, to provide some variation.


 * Extreme Hills
 * Renamed mountains to extreme hills, and gravelly mountains to gravelly hills.


 * Mountains
 * Sheep now spawn in meadows.
 * Rabbits now spawn more frequently in meadows.
 * Donkeys now spawn less frequently in meadows.
 * Blue orchid no longer spawns in meadows.
 * Meadows sometimes spawn a lone oak or birch, often with a bee nest.
 * Hostile mobs now spawn in the new mountain biomes.
 * Infested stone now generate in the new mountain biomes.


 * Ore distribution
 * Emerald ores now generate in the new mountain biomes.


 * Ore veins
 * Made ore veins slightly larger and more frequent.


 * Biomes
 * Re-added ice spikes, eroded badlands and savanna plateau.


 * Swamp
 * Swamps now generate properly.


 * Lush Caves
 * Are now slightly smaller and slightly less common.


 * General
 * Biome placement is a bit smoother and less noisy. Fewer microbiomes dotting the terrain. Biomes tend to be a bit larger and less fragmented.
 * Underground biomes interfere less with surface biomes. They can still leak out of cave entrances sometimes.
 * Increased the height of some of the peaks.
 * Now can rarely reach up to Y=260.
 * Slightly increased the chance of finding large areas with flat terrain.
 * Structures now mostly show up in the right biomes.
 * Toned down the megacave entrances a little bit, and made them less likely to go all the way down to deepslate level.
 * Made cheese caves a little bit smaller on average, and a bit less likely to intersect the surface.
 * Reduced the chance of sand and gravel being placed in such a way that they immediately fall down on generation.
 * Some are now replaced with sandstone or stone.

General

 * Clouds
 * Raised cloud level from 128 to 192.

Trivia

 * Unlike 1.18 Experimental Snapshot 1, the title of this version is written in lowercase.

Issues
This version is not supported on the bug tracker, and therefore issues affecting it will be resolved as "Invalid".

Video
Video made by slicedlime: