command | Added the /jfr command, along with the --jfrProfile startup option
text font | Added illageralt rule-like font from Minecraft Dungeons
loot item-modifier | The set_contents and set_loot_table functions now require a type field with a valid block entity type
pack-format | Data pack format has been increased to 8
command scoreboard | Removed length limits for scoreboard objectives, score holders (fake players), and team names
nbt | Added custom_spawn_rules NBT field to spawners, in the SpawnData object and SpawnPotentials list.
nbt | Changed spawner NBT field SpawnPotentials format to { weight: <int>, data: { entity: {...}, custom_spawn_rules: {...} } }
nbt | Moved contents of spawner NBT field SpawnData to SpawnData.entity
data tag | Renamed block tag lava_pool_stone_replaceables to lava_pool_stone_cannot_replace
worldgen | Removed seed field from the multi_noise biome source
worldgen | Removed altitude_noise, temperature_noise, humidity_noise and weirdness_noise fields from the multi_noise biome source, and added octaves field to noise settings, used for both the biome and terrain noise
worldgen | Removed the vanilla_layered biome source
worldgen | Removed altitude biome noise parameter
worldgen | Added continentalness, erosion and depth biome noise parameters
worldgen | Multi noise debug values show on the F3 screen
worldgen | Removed scale and depth fields from biomes, since terrain is now shaped independently from biome placement
worldgen | Removed starts field from biomes
worldgen | Added mob category axolotls
worldgen data | Added surface builders grove, lofty_peaks, snowcapped_peaks, snowy_slopes, stone_shore, and stony_peaks
worldgen | Added decorator surface_relative_threshold
worldgen | Removed block state providers forest_flower_provider and plain_flower_provider
worldgen | Added block state providers dual_noise_2d_provider, noise_2d_cutoff_provider, and noise_2d_provider
worldgen | Removed field min_surface_level from noise settings