26.3 Snapshot 1 — release journal

What 26.3-snapshot-1 changed for data packs, measured against 26.2, the build before it. Released 2026-06-23; development build — not a release.

⚠ Breaking for data packs

This build removed 2 registries. Any file that referenced them stops loading. tag/worldgen/configured_feature looks renamed to tag/worldgen/feature (100% of its entries reappear there) — in those cases the fix is likely moving files, not rewriting them.

Formats

	26.2	26.3-snapshot-1
Data pack format	107.1	108.0 moved
Resource pack format	88.0	89.0 moved
Data version	4903	4998

Registries

1,464 entries added and 346 removed across 48 registries.

Registry	Change	Added	Removed
`tag/worldgen/configured_feature`	registry removed — likely renamed to `tag/worldgen/feature`	—	`can_spawn_from_bone_meal`
`worldgen/configured_feature`	registry removed	—	`acacia`, `amethyst_geode`, `azalea_tree`, `bamboo_no_podzol`, `bamboo_some_podzol`, `bamboo_vegetation`, `basalt_blobs`, `basalt_pillar`, `berry_bush`, `birch`, `birch_bees_0002`, `birch_bees_0002_leaf_litter`, `birch_bees_002`, `birch_bees_005`, `birch_leaf_litter`, `birch_tall`, `blackstone_blobs`, `blue_ice`, `bonus_chest`, `brown_mushroom`, `bush`, `cactus`, `cave_vine`, `cave_vine_in_moss`, `cherry`, `cherry_bees_005`, `chorus_plant`, `clay_pool_with_dripleaves`, `clay_with_dripleaves`, `crimson_forest_vegetation`, `crimson_forest_vegetation_bonemeal`, `crimson_fungus`, `crimson_fungus_planted`, `crimson_roots`, `dark_forest_vegetation`, `dark_oak`, `dark_oak_leaf_litter`, `dead_bush`, `delta`, `desert_well`, `disk_clay`, `disk_grass`, `disk_gravel`, `disk_sand`, `dripleaf`, `dripstone_cluster`, `dry_grass`, `end_gateway_delayed`, `end_gateway_return`, `end_island`, `end_platform`, `end_spike`, `fallen_birch_tree`, `fallen_jungle_tree`, `fallen_oak_tree`, `fallen_spruce_tree`, `fallen_super_birch_tree`, `fancy_oak`, `fancy_oak_bees`, `fancy_oak_bees_0002_leaf_litter` and 166 more
`tag/worldgen/feature`	new registry	`can_spawn_from_bone_meal`	—
`worldgen/feature_type`	new registry	`bamboo`, `basalt_columns`, `basalt_pillar`, `block_blob`, `block_column`, `block_pile`, `blue_ice`, `bonus_chest`, `chorus_plant`, `coral_claw`, `coral_mushroom`, `coral_tree`, `delta_feature`, `desert_well`, `disk`, `end_gateway`, `end_island`, `end_platform`, `end_podium`, `end_spike`, `fallen_tree`, `fill_layer`, `fossil`, `freeze_top_layer`, `geode`, `glowstone_blob`, `huge_brown_mushroom`, `huge_fungus`, `huge_red_mushroom`, `iceberg`, `kelp`, `lake`, `large_dripstone`, `monster_room`, `multiface_growth`, `nether_forest_vegetation`, `netherrack_replace_blobs`, `no_op`, `ore`, `random_boolean_selector`, `random_selector`, `replace_single_block`, `root_system`, `scattered_ore`, `sculk_patch`, `sea_pickle`, `seagrass`, `sequence`, `simple_block`, `simple_random_selector`, `speleothem`, `speleothem_cluster`, `spike`, `spring_feature`, `template`, `tree`, `twisting_vines`, `underwater_magma`, `vegetation_patch`, `vines` and 4 more	—
`worldgen/material_condition_type`	new registry	`above_preliminary_surface`, `biome`, `hole`, `noise_threshold`, `not`, `steep`, `stone_depth`, `temperature`, `vertical_gradient`, `water`, `y_above`	—
`worldgen/material_rule_type`	new registry	`bandlands`, `block`, `condition`, `sequence`	—
`advancement`	changed	`recipes/building_blocks/black_wool_slab`, `recipes/building_blocks/black_wool_stairs`, `recipes/building_blocks/blue_wool_slab`, `recipes/building_blocks/blue_wool_stairs`, `recipes/building_blocks/brown_wool_slab`, `recipes/building_blocks/brown_wool_stairs`, `recipes/building_blocks/cyan_wool_slab`, `recipes/building_blocks/cyan_wool_stairs`, `recipes/building_blocks/dye_black_wool_slab`, `recipes/building_blocks/dye_black_wool_stairs`, `recipes/building_blocks/dye_blue_wool_slab`, `recipes/building_blocks/dye_blue_wool_stairs`, `recipes/building_blocks/dye_brown_wool_slab`, `recipes/building_blocks/dye_brown_wool_stairs`, `recipes/building_blocks/dye_cyan_wool_slab`, `recipes/building_blocks/dye_cyan_wool_stairs`, `recipes/building_blocks/dye_gray_wool_slab`, `recipes/building_blocks/dye_gray_wool_stairs`, `recipes/building_blocks/dye_green_wool_slab`, `recipes/building_blocks/dye_green_wool_stairs`, `recipes/building_blocks/dye_light_blue_wool_slab`, `recipes/building_blocks/dye_light_blue_wool_stairs`, `recipes/building_blocks/dye_light_gray_wool_slab`, `recipes/building_blocks/dye_light_gray_wool_stairs`, `recipes/building_blocks/dye_lime_wool_slab`, `recipes/building_blocks/dye_lime_wool_stairs`, `recipes/building_blocks/dye_magenta_wool_slab`, `recipes/building_blocks/dye_magenta_wool_stairs`, `recipes/building_blocks/dye_orange_wool_slab`, `recipes/building_blocks/dye_orange_wool_stairs`, `recipes/building_blocks/dye_pink_wool_slab`, `recipes/building_blocks/dye_pink_wool_stairs`, `recipes/building_blocks/dye_purple_wool_slab`, `recipes/building_blocks/dye_purple_wool_stairs`, `recipes/building_blocks/dye_red_wool_slab`, `recipes/building_blocks/dye_red_wool_stairs`, `recipes/building_blocks/dye_white_wool_slab`, `recipes/building_blocks/dye_white_wool_stairs`, `recipes/building_blocks/dye_yellow_wool_slab`, `recipes/building_blocks/dye_yellow_wool_stairs`, `recipes/building_blocks/gray_wool_slab`, `recipes/building_blocks/gray_wool_stairs`, `recipes/building_blocks/green_wool_slab`, `recipes/building_blocks/green_wool_stairs`, `recipes/building_blocks/light_blue_wool_slab`, `recipes/building_blocks/light_blue_wool_stairs`, `recipes/building_blocks/light_gray_wool_slab`, `recipes/building_blocks/light_gray_wool_stairs`, `recipes/building_blocks/lime_wool_slab`, `recipes/building_blocks/lime_wool_stairs`, `recipes/building_blocks/magenta_wool_slab`, `recipes/building_blocks/magenta_wool_stairs`, `recipes/building_blocks/orange_wool_slab`, `recipes/building_blocks/orange_wool_stairs`, `recipes/building_blocks/pink_wool_slab`, `recipes/building_blocks/pink_wool_stairs`, `recipes/building_blocks/poplar_planks`, `recipes/building_blocks/poplar_slab`, `recipes/building_blocks/poplar_stairs`, `recipes/building_blocks/poplar_wood` and 21 more	`recipes/decorations/black_carpet`, `recipes/decorations/blue_carpet`, `recipes/decorations/brown_carpet`, `recipes/decorations/cyan_carpet`, `recipes/decorations/gray_carpet`, `recipes/decorations/green_carpet`, `recipes/decorations/light_blue_carpet`, `recipes/decorations/light_gray_carpet`, `recipes/decorations/lime_carpet`, `recipes/decorations/magenta_carpet`, `recipes/decorations/orange_carpet`, `recipes/decorations/pink_carpet`, `recipes/decorations/purple_carpet`, `recipes/decorations/red_carpet`, `recipes/decorations/white_carpet`, `recipes/decorations/yellow_carpet`
`atlas`	changed	—	`armor_trims`
`block`	changed	`black_wool_slab`, `black_wool_stairs`, `blue_wool_slab`, `blue_wool_stairs`, `brown_wool_slab`, `brown_wool_stairs`, `cyan_wool_slab`, `cyan_wool_stairs`, `gray_wool_slab`, `gray_wool_stairs`, `green_wool_slab`, `green_wool_stairs`, `light_blue_wool_slab`, `light_blue_wool_stairs`, `light_gray_wool_slab`, `light_gray_wool_stairs`, `lime_wool_slab`, `lime_wool_stairs`, `magenta_wool_slab`, `magenta_wool_stairs`, `orange_poplar_leaves`, `orange_wool_slab`, `orange_wool_stairs`, `pink_wool_slab`, `pink_wool_stairs`, `poplar_button`, `poplar_door`, `poplar_fence`, `poplar_fence_gate`, `poplar_hanging_sign`, `poplar_log`, `poplar_planks`, `poplar_pressure_plate`, `poplar_sapling`, `poplar_shelf`, `poplar_sign`, `poplar_slab`, `poplar_stairs`, `poplar_trapdoor`, `poplar_wall_hanging_sign`, `poplar_wall_sign`, `poplar_wood`, `potted_poplar_sapling`, `purple_wool_slab`, `purple_wool_stairs`, `red_poplar_leaves`, `red_shrub`, `red_wool_slab`, `red_wool_stairs`, `shelf_mushroom`, `stripped_poplar_log`, `stripped_poplar_wood`, `white_wool_slab`, `white_wool_stairs`, `yellow_poplar_leaves`, `yellow_wool_slab`, `yellow_wool_stairs`	—
`block_definition`	changed	`black_wool_slab`, `black_wool_stairs`, `blue_wool_slab`, `blue_wool_stairs`, `brown_wool_slab`, `brown_wool_stairs`, `cyan_wool_slab`, `cyan_wool_stairs`, `gray_wool_slab`, `gray_wool_stairs`, `green_wool_slab`, `green_wool_stairs`, `light_blue_wool_slab`, `light_blue_wool_stairs`, `light_gray_wool_slab`, `light_gray_wool_stairs`, `lime_wool_slab`, `lime_wool_stairs`, `magenta_wool_slab`, `magenta_wool_stairs`, `orange_poplar_leaves`, `orange_wool_slab`, `orange_wool_stairs`, `pink_wool_slab`, `pink_wool_stairs`, `poplar_button`, `poplar_door`, `poplar_fence`, `poplar_fence_gate`, `poplar_hanging_sign`, `poplar_log`, `poplar_planks`, `poplar_pressure_plate`, `poplar_sapling`, `poplar_shelf`, `poplar_sign`, `poplar_slab`, `poplar_stairs`, `poplar_trapdoor`, `poplar_wall_hanging_sign`, `poplar_wall_sign`, `poplar_wood`, `potted_poplar_sapling`, `purple_wool_slab`, `purple_wool_stairs`, `red_poplar_leaves`, `red_shrub`, `red_wool_slab`, `red_wool_stairs`, `shelf_mushroom`, `stripped_poplar_log`, `stripped_poplar_wood`, `white_wool_slab`, `white_wool_stairs`, `yellow_poplar_leaves`, `yellow_wool_slab`, `yellow_wool_stairs`	—
`block_type`	changed	`leaves`, `path`, `shelf_mushroom`	`dirt_path`
`command_argument_type`	changed	`slot_source`	—
`data_component_type`	changed	`provides_pottery_pattern`	—
`decorated_pot_pattern`	changed	—	`blank`
`entity_type`	changed	`poplar_boat`, `poplar_chest_boat`	—
`item`	changed	`black_wool_slab`, `black_wool_stairs`, `blue_wool_slab`, `blue_wool_stairs`, `brown_wool_slab`, `brown_wool_stairs`, `cyan_wool_slab`, `cyan_wool_stairs`, `gray_wool_slab`, `gray_wool_stairs`, `green_wool_slab`, `green_wool_stairs`, `light_blue_wool_slab`, `light_blue_wool_stairs`, `light_gray_wool_slab`, `light_gray_wool_stairs`, `lime_wool_slab`, `lime_wool_stairs`, `magenta_wool_slab`, `magenta_wool_stairs`, `orange_poplar_leaves`, `orange_wool_slab`, `orange_wool_stairs`, `pink_wool_slab`, `pink_wool_stairs`, `poplar_boat`, `poplar_button`, `poplar_chest_boat`, `poplar_door`, `poplar_fence`, `poplar_fence_gate`, `poplar_hanging_sign`, `poplar_log`, `poplar_planks`, `poplar_pressure_plate`, `poplar_sapling`, `poplar_shelf`, `poplar_sign`, `poplar_slab`, `poplar_stairs`, `poplar_trapdoor`, `poplar_wood`, `purple_wool_slab`, `purple_wool_stairs`, `red_poplar_leaves`, `red_shrub`, `red_wool_slab`, `red_wool_stairs`, `shelf_mushroom`, `stripped_poplar_log`, `stripped_poplar_wood`, `white_wool_slab`, `white_wool_stairs`, `yellow_poplar_leaves`, `yellow_wool_slab`, `yellow_wool_stairs`	—
`item_definition`	changed	`black_wool_slab`, `black_wool_stairs`, `blue_wool_slab`, `blue_wool_stairs`, `brown_wool_slab`, `brown_wool_stairs`, `cyan_wool_slab`, `cyan_wool_stairs`, `gray_wool_slab`, `gray_wool_stairs`, `green_wool_slab`, `green_wool_stairs`, `light_blue_wool_slab`, `light_blue_wool_stairs`, `light_gray_wool_slab`, `light_gray_wool_stairs`, `lime_wool_slab`, `lime_wool_stairs`, `magenta_wool_slab`, `magenta_wool_stairs`, `orange_poplar_leaves`, `orange_wool_slab`, `orange_wool_stairs`, `pink_wool_slab`, `pink_wool_stairs`, `poplar_boat`, `poplar_button`, `poplar_chest_boat`, `poplar_door`, `poplar_fence`, `poplar_fence_gate`, `poplar_hanging_sign`, `poplar_log`, `poplar_planks`, `poplar_pressure_plate`, `poplar_sapling`, `poplar_shelf`, `poplar_sign`, `poplar_slab`, `poplar_stairs`, `poplar_trapdoor`, `poplar_wood`, `purple_wool_slab`, `purple_wool_stairs`, `red_poplar_leaves`, `red_shrub`, `red_wool_slab`, `red_wool_stairs`, `shelf_mushroom`, `stripped_poplar_log`, `stripped_poplar_wood`, `white_wool_slab`, `white_wool_stairs`, `yellow_poplar_leaves`, `yellow_wool_slab`, `yellow_wool_stairs`	—
`loot_table`	changed	`barrels/abandoned_camp_barrel`, `blocks/black_wool_slab`, `blocks/black_wool_stairs`, `blocks/blue_wool_slab`, `blocks/blue_wool_stairs`, `blocks/brown_wool_slab`, `blocks/brown_wool_stairs`, `blocks/cyan_wool_slab`, `blocks/cyan_wool_stairs`, `blocks/gray_wool_slab`, `blocks/gray_wool_stairs`, `blocks/green_wool_slab`, `blocks/green_wool_stairs`, `blocks/light_blue_wool_slab`, `blocks/light_blue_wool_stairs`, `blocks/light_gray_wool_slab`, `blocks/light_gray_wool_stairs`, `blocks/lime_wool_slab`, `blocks/lime_wool_stairs`, `blocks/magenta_wool_slab`, `blocks/magenta_wool_stairs`, `blocks/orange_poplar_leaves`, `blocks/orange_wool_slab`, `blocks/orange_wool_stairs`, `blocks/pink_wool_slab`, `blocks/pink_wool_stairs`, `blocks/poplar_button`, `blocks/poplar_door`, `blocks/poplar_fence`, `blocks/poplar_fence_gate`, `blocks/poplar_hanging_sign`, `blocks/poplar_log`, `blocks/poplar_planks`, `blocks/poplar_pressure_plate`, `blocks/poplar_sapling`, `blocks/poplar_shelf`, `blocks/poplar_sign`, `blocks/poplar_slab`, `blocks/poplar_stairs`, `blocks/poplar_trapdoor`, `blocks/poplar_wood`, `blocks/potted_poplar_sapling`, `blocks/purple_wool_slab`, `blocks/purple_wool_stairs`, `blocks/red_poplar_leaves`, `blocks/red_shrub`, `blocks/red_wool_slab`, `blocks/red_wool_stairs`, `blocks/shelf_mushroom`, `blocks/stripped_poplar_log`, `blocks/stripped_poplar_wood`, `blocks/white_wool_slab`, `blocks/white_wool_stairs`, `blocks/yellow_poplar_leaves`, `blocks/yellow_wool_slab`, `blocks/yellow_wool_stairs`, `chests/abandoned_camp_common_chest`, `chests/abandoned_camp_secret_chest`	—
`model`	changed	`block/black_wool_slab`, `block/black_wool_slab_top`, `block/black_wool_stairs`, `block/black_wool_stairs_inner`, `block/black_wool_stairs_outer`, `block/blue_wool_slab`, `block/blue_wool_slab_top`, `block/blue_wool_stairs`, `block/blue_wool_stairs_inner`, `block/blue_wool_stairs_outer`, `block/brown_wool_slab`, `block/brown_wool_slab_top`, `block/brown_wool_stairs`, `block/brown_wool_stairs_inner`, `block/brown_wool_stairs_outer`, `block/cyan_wool_slab`, `block/cyan_wool_slab_top`, `block/cyan_wool_stairs`, `block/cyan_wool_stairs_inner`, `block/cyan_wool_stairs_outer`, `block/gray_wool_slab`, `block/gray_wool_slab_top`, `block/gray_wool_stairs`, `block/gray_wool_stairs_inner`, `block/gray_wool_stairs_outer`, `block/green_wool_slab`, `block/green_wool_slab_top`, `block/green_wool_stairs`, `block/green_wool_stairs_inner`, `block/green_wool_stairs_outer`, `block/light_blue_wool_slab`, `block/light_blue_wool_slab_top`, `block/light_blue_wool_stairs`, `block/light_blue_wool_stairs_inner`, `block/light_blue_wool_stairs_outer`, `block/light_gray_wool_slab`, `block/light_gray_wool_slab_top`, `block/light_gray_wool_stairs`, `block/light_gray_wool_stairs_inner`, `block/light_gray_wool_stairs_outer`, `block/lime_wool_slab`, `block/lime_wool_slab_top`, `block/lime_wool_stairs`, `block/lime_wool_stairs_inner`, `block/lime_wool_stairs_outer`, `block/magenta_wool_slab`, `block/magenta_wool_slab_top`, `block/magenta_wool_stairs`, `block/magenta_wool_stairs_inner`, `block/magenta_wool_stairs_outer`, `block/orange_poplar_leaves`, `block/orange_wool_slab`, `block/orange_wool_slab_top`, `block/orange_wool_stairs`, `block/orange_wool_stairs_inner`, `block/orange_wool_stairs_outer`, `block/pink_wool_slab`, `block/pink_wool_slab_top`, `block/pink_wool_stairs`, `block/pink_wool_stairs_inner` and 92 more	`block/template_farmland`
`outgoing_rpc_methods`	changed	`notification/world/upgrade_failed`, `notification/world/upgrade_finished`, `notification/world/upgrade_progress`, `notification/world/upgrade_started`	—
`particle_type`	changed	`orange_poplar_leaves`, `red_poplar_leaves`, `yellow_poplar_leaves`	—
`recipe`	changed	`black_wool_slab`, `black_wool_stairs`, `blue_wool_slab`, `blue_wool_stairs`, `brown_wool_slab`, `brown_wool_stairs`, `cyan_wool_slab`, `cyan_wool_stairs`, `dye_black_wool_slab`, `dye_black_wool_stairs`, `dye_blue_wool_slab`, `dye_blue_wool_stairs`, `dye_brown_wool_slab`, `dye_brown_wool_stairs`, `dye_cyan_wool_slab`, `dye_cyan_wool_stairs`, `dye_gray_wool_slab`, `dye_gray_wool_stairs`, `dye_green_wool_slab`, `dye_green_wool_stairs`, `dye_light_blue_wool_slab`, `dye_light_blue_wool_stairs`, `dye_light_gray_wool_slab`, `dye_light_gray_wool_stairs`, `dye_lime_wool_slab`, `dye_lime_wool_stairs`, `dye_magenta_wool_slab`, `dye_magenta_wool_stairs`, `dye_orange_wool_slab`, `dye_orange_wool_stairs`, `dye_pink_wool_slab`, `dye_pink_wool_stairs`, `dye_purple_wool_slab`, `dye_purple_wool_stairs`, `dye_red_wool_slab`, `dye_red_wool_stairs`, `dye_white_wool_slab`, `dye_white_wool_stairs`, `dye_yellow_wool_slab`, `dye_yellow_wool_stairs`, `gray_wool_slab`, `gray_wool_stairs`, `green_wool_slab`, `green_wool_stairs`, `light_blue_wool_slab`, `light_blue_wool_stairs`, `light_gray_wool_slab`, `light_gray_wool_stairs`, `lime_wool_slab`, `lime_wool_stairs`, `magenta_wool_slab`, `magenta_wool_stairs`, `orange_wool_slab`, `orange_wool_stairs`, `pink_wool_slab`, `pink_wool_stairs`, `poplar_boat`, `poplar_button`, `poplar_chest_boat`, `poplar_door` and 21 more	`black_carpet`, `blue_carpet`, `brown_carpet`, `cyan_carpet`, `gray_carpet`, `green_carpet`, `light_blue_carpet`, `light_gray_carpet`, `lime_carpet`, `magenta_carpet`, `orange_carpet`, `pink_carpet`, `purple_carpet`, `red_carpet`, `white_carpet`, `yellow_carpet`
`rule_test`	changed	`all_of`, `height_match`	—
`slot_source_type`	changed	`reference`	—
`sound`	changed	`block/poplar_leaves/ambient1`, `block/poplar_leaves/ambient10`, `block/poplar_leaves/ambient11`, `block/poplar_leaves/ambient12`, `block/poplar_leaves/ambient13`, `block/poplar_leaves/ambient14`, `block/poplar_leaves/ambient15`, `block/poplar_leaves/ambient17`, `block/poplar_leaves/ambient18`, `block/poplar_leaves/ambient19`, `block/poplar_leaves/ambient2`, `block/poplar_leaves/ambient3`, `block/poplar_leaves/ambient4`, `block/poplar_leaves/ambient5`, `block/poplar_leaves/ambient6`, `block/poplar_leaves/ambient7`, `block/poplar_leaves/ambient8`, `block/poplar_leaves/ambient9`, `block/poplar_leaves/wind1`, `block/poplar_leaves/wind2`, `block/poplar_leaves/wind3`, `block/shelf_mushroom/bounce1`, `block/shelf_mushroom/bounce2`, `block/shelf_mushroom/bounce3`, `block/shelf_mushroom/bounce4`, `block/shelf_mushroom/bounce5`, `block/shelf_mushroom/bounce6`, `block/shelf_mushroom/break1`, `block/shelf_mushroom/break2`, `block/shelf_mushroom/break3`, `block/shelf_mushroom/break4`, `block/shelf_mushroom/break5`, `block/shelf_mushroom/break6`, `block/shelf_mushroom/place1`, `block/shelf_mushroom/place2`, `block/shelf_mushroom/place3`, `block/shelf_mushroom/place4`, `block/shelf_mushroom/place5`, `block/shelf_mushroom/place6`, `block/shelf_mushroom/step1`, `block/shelf_mushroom/step2`, `block/shelf_mushroom/step3`, `block/shelf_mushroom/step4`, `block/shelf_mushroom/step5`, `block/shelf_mushroom/step6`, `mob/sulfur_cube/ball/slowsliding_hit1`, `mob/sulfur_cube/ball/slowsliding_hit2`, `mob/sulfur_cube/ball/slowsliding_hit3`, `mob/sulfur_cube/ball/slowsliding_hit4`	`mob/sulfur_cube/ball/hit1`, `mob/sulfur_cube/ball/hit2`, `mob/sulfur_cube/ball/hit3`, `mob/sulfur_cube/ball/hit4`, `mob/sulfur_cube/ball/push1`, `mob/sulfur_cube/ball/push2`, `mob/sulfur_cube/ball/push3`, `mob/sulfur_cube/ball/push4`
`sound_event`	changed	`block.poplar_leaves.ambient`, `block.shelf_mushroom.bounce`, `block.shelf_mushroom.break`, `block.shelf_mushroom.fall`, `block.shelf_mushroom.place`, `block.shelf_mushroom.step`	—
`structure`	changed	`abandoned_camp/camp/bamboo_jungle/campsite_bamboo_jungle_1`, `abandoned_camp/camp/bamboo_jungle/campsite_bamboo_jungle_2`, `abandoned_camp/camp/bamboo_jungle/campsite_bamboo_jungle_3`, `abandoned_camp/camp/birch_forest/campsite_birch_forest_1`, `abandoned_camp/camp/birch_forest/campsite_birch_forest_2`, `abandoned_camp/camp/birch_forest/campsite_birch_forest_3`, `abandoned_camp/camp/cherry_grove/campsite_cherry_grove_1`, `abandoned_camp/camp/cherry_grove/campsite_cherry_grove_2`, `abandoned_camp/camp/cherry_grove/campsite_cherry_grove_3`, `abandoned_camp/camp/dappled_forest/campsite_dappled_forest_1`, `abandoned_camp/camp/dappled_forest/campsite_dappled_forest_2`, `abandoned_camp/camp/dappled_forest/campsite_dappled_forest_3`, `abandoned_camp/camp/default/campsite_default_barrel_1`, `abandoned_camp/camp/default/campsite_default_barrel_10`, `abandoned_camp/camp/default/campsite_default_barrel_11`, `abandoned_camp/camp/default/campsite_default_barrel_12`, `abandoned_camp/camp/default/campsite_default_barrel_13`, `abandoned_camp/camp/default/campsite_default_barrel_14`, `abandoned_camp/camp/default/campsite_default_barrel_15`, `abandoned_camp/camp/default/campsite_default_barrel_2`, `abandoned_camp/camp/default/campsite_default_barrel_3`, `abandoned_camp/camp/default/campsite_default_barrel_4`, `abandoned_camp/camp/default/campsite_default_barrel_5`, `abandoned_camp/camp/default/campsite_default_barrel_6`, `abandoned_camp/camp/default/campsite_default_barrel_7`, `abandoned_camp/camp/default/campsite_default_barrel_8`, `abandoned_camp/camp/default/campsite_default_barrel_9`, `abandoned_camp/camp/default/campsite_default_chest_1`, `abandoned_camp/camp/default/campsite_default_chest_10`, `abandoned_camp/camp/default/campsite_default_chest_11`, `abandoned_camp/camp/default/campsite_default_chest_12`, `abandoned_camp/camp/default/campsite_default_chest_13`, `abandoned_camp/camp/default/campsite_default_chest_14`, `abandoned_camp/camp/default/campsite_default_chest_15`, `abandoned_camp/camp/default/campsite_default_chest_2`, `abandoned_camp/camp/default/campsite_default_chest_3`, `abandoned_camp/camp/default/campsite_default_chest_4`, `abandoned_camp/camp/default/campsite_default_chest_5`, `abandoned_camp/camp/default/campsite_default_chest_6`, `abandoned_camp/camp/default/campsite_default_chest_7`, `abandoned_camp/camp/default/campsite_default_chest_8`, `abandoned_camp/camp/default/campsite_default_chest_9`, `abandoned_camp/camp/default/campsite_default_special_1`, `abandoned_camp/camp/default/campsite_default_special_10`, `abandoned_camp/camp/default/campsite_default_special_11`, `abandoned_camp/camp/default/campsite_default_special_12`, `abandoned_camp/camp/default/campsite_default_special_13`, `abandoned_camp/camp/default/campsite_default_special_14`, `abandoned_camp/camp/default/campsite_default_special_15`, `abandoned_camp/camp/default/campsite_default_special_2`, `abandoned_camp/camp/default/campsite_default_special_3`, `abandoned_camp/camp/default/campsite_default_special_4`, `abandoned_camp/camp/default/campsite_default_special_5`, `abandoned_camp/camp/default/campsite_default_special_6`, `abandoned_camp/camp/default/campsite_default_special_7`, `abandoned_camp/camp/default/campsite_default_special_8`, `abandoned_camp/camp/default/campsite_default_special_9`, `abandoned_camp/camp/flower_forest/campsite_flower_forest_1`, `abandoned_camp/camp/flower_forest/campsite_flower_forest_2`, `abandoned_camp/camp/flower_forest/campsite_flower_forest_3` and 219 more	—
`tag/block`	changed	`blocks_dolphin_jump`, `blocks_fluid_flow`, `blocks_lava_fire_spread`, `blocks_motion`, `blocks_motion_in_heightmap`, `blocks_motion_in_heightmap_no_leaves`, `blocks_motion_no_leaves`, `causes_suffocation`, `entities_can_teleport_to`, `ice_melts_when_destroyed_above`, `ores`, `poplar_logs`, `required_for_poplar_leaf_ambience`, `skulls`, `washed_away_by_fluids`, `wool_slabs`, `wool_stairs`	—
`tag/damage_type`	changed	`no_wolf_retaliation`	—
`tag/entity_type`	changed	`cannot_be_dismounted_by_item_usage`	—
`tag/item`	changed	`mushrooms`, `ores`, `poplar_logs`, `wool_slabs`, `wool_stairs`	—
`tag/worldgen/biome`	changed	`has_structure/abandoned_camp_bamboo_jungle`, `has_structure/abandoned_camp_birch_forest`, `has_structure/abandoned_camp_cherry_grove`, `has_structure/abandoned_camp_dappled_forest`, `has_structure/abandoned_camp_flower_forest`, `has_structure/abandoned_camp_forest`, `has_structure/abandoned_camp_meadow`, `has_structure/abandoned_camp_old_growth_birch_forest`, `has_structure/abandoned_camp_old_growth_pine_taiga`, `has_structure/abandoned_camp_old_growth_spruce_taiga`, `has_structure/abandoned_camp_pale_garden`, `has_structure/abandoned_camp_savanna`, `has_structure/abandoned_camp_snowy_taiga`, `has_structure/abandoned_camp_sparse_jungle`, `has_structure/abandoned_camp_swamp`, `has_structure/abandoned_camp_taiga`, `has_structure/abandoned_camp_windswept_forest`, `has_structure/abandoned_camp_wooded_badlands`	—
`test_environment_definition_type`	changed	`dimension`	—
`texture`	changed	`block/orange_poplar_leaves`, `block/poplar_door_bottom`, `block/poplar_door_top`, `block/poplar_hanging_sign`, `block/poplar_log`, `block/poplar_log_top`, `block/poplar_planks`, `block/poplar_sapling`, `block/poplar_shelf`, `block/poplar_sign`, `block/poplar_trapdoor`, `block/red_poplar_leaves`, `block/red_shrub`, `block/shelf_mushroom_stage0`, `block/shelf_mushroom_stage1`, `block/stripped_poplar_log`, `block/stripped_poplar_log_top`, `block/yellow_poplar_leaves`, `entity/boat/poplar`, `entity/chest_boat/poplar`, `gui/hanging_signs/poplar`, `gui/signs/poplar`, `item/poplar_boat`, `item/poplar_chest_boat`, `item/poplar_door`, `item/poplar_hanging_sign`, `item/poplar_sign`, `palettes/trim/amethyst`, `palettes/trim/copper`, `palettes/trim/copper_darker`, `palettes/trim/diamond`, `palettes/trim/diamond_darker`, `palettes/trim/emerald`, `palettes/trim/gold`, `palettes/trim/gold_darker`, `palettes/trim/iron`, `palettes/trim/iron_darker`, `palettes/trim/lapis`, `palettes/trim/netherite`, `palettes/trim/netherite_darker`, `palettes/trim/quartz`, `palettes/trim/redstone`, `palettes/trim/resin`, `palettes/trim_base`, `particle/orange_poplar_1`, `particle/orange_poplar_2`, `particle/orange_poplar_3`, `particle/orange_poplar_4`, `particle/red_poplar_1`, `particle/red_poplar_2`, `particle/red_poplar_3`, `particle/red_poplar_4`, `particle/yellow_poplar_1`, `particle/yellow_poplar_2`, `particle/yellow_poplar_3`, `particle/yellow_poplar_4`	`trims/color_palettes/amethyst`, `trims/color_palettes/copper`, `trims/color_palettes/copper_darker`, `trims/color_palettes/diamond`, `trims/color_palettes/diamond_darker`, `trims/color_palettes/emerald`, `trims/color_palettes/gold`, `trims/color_palettes/gold_darker`, `trims/color_palettes/iron`, `trims/color_palettes/iron_darker`, `trims/color_palettes/lapis`, `trims/color_palettes/netherite`, `trims/color_palettes/netherite_darker`, `trims/color_palettes/quartz`, `trims/color_palettes/redstone`, `trims/color_palettes/resin`, `trims/color_palettes/trim_palette`
`villager_trade`	changed	`wandering_trader/emerald_poplar_sapling`, `wandering_trader/emerald_shelf_mushroom`	—
`worldgen/biome`	changed	`dappled_forest`	—
`worldgen/feature`	changed	`acacia`, `amethyst_geode`, `azalea_tree`, `bamboo_no_podzol`, `bamboo_some_podzol`, `bamboo_vegetation`, `basalt_blobs`, `berry_bush`, `birch`, `birch_bees_0002`, `birch_bees_0002_leaf_litter`, `birch_bees_002`, `birch_bees_005`, `birch_leaf_litter`, `birch_tall`, `blackstone_blobs`, `brown_mushroom`, `bush`, `cactus`, `cave_vine`, `cave_vine_in_moss`, `cherry`, `cherry_bees_005`, `clay_pool_with_dripleaves`, `clay_with_dripleaves`, `crimson_forest_vegetation`, `crimson_forest_vegetation_bonemeal`, `crimson_fungus`, `crimson_fungus_planted`, `crimson_roots`, `dark_forest_vegetation`, `dark_oak`, `dark_oak_leaf_litter`, `dead_bush`, `delta`, `disk_clay`, `disk_grass`, `disk_gravel`, `disk_sand`, `dripleaf`, `dripstone_cluster`, `dry_grass`, `end_gateway_delayed`, `end_gateway_return`, `end_podium_active`, `end_podium_inactive`, `fallen_birch_tree`, `fallen_jungle_tree`, `fallen_oak_tree`, `fallen_poplar_tree`, `fallen_spruce_tree`, `fallen_super_birch_tree`, `fancy_oak`, `fancy_oak_bees`, `fancy_oak_bees_0002_leaf_litter`, `fancy_oak_bees_002`, `fancy_oak_bees_005`, `fancy_oak_leaf_litter`, `firefly_bush`, `flower_cherry` and 157 more	`bamboo`, `basalt_columns`, `block_blob`, `block_column`, `block_pile`, `coral_claw`, `coral_mushroom`, `coral_tree`, `delta_feature`, `disk`, `end_gateway`, `fallen_tree`, `fill_layer`, `fossil`, `geode`, `glowstone_blob`, `huge_fungus`, `iceberg`, `lake`, `multiface_growth`, `nether_forest_vegetation`, `netherrack_replace_blobs`, `no_op`, `ore`, `random_boolean_selector`, `random_selector`, `replace_single_block`, `root_system`, `scattered_ore`, `sculk_patch`, `seagrass`, `sequence`, `simple_block`, `simple_random_selector`, `speleothem`, `speleothem_cluster`, `spike`, `spring_feature`, `template`, `tree`, `vegetation_patch`, `waterlogged_vegetation_patch`, `weighted_random_selector`
`worldgen/foliage_placer_type`	changed	`poplar_foliage_placer`	—
`worldgen/material_condition`	changed	`above_water`, `deep_under_floor`, `not_under_deep_water`, `not_underwater`, `on_ceiling`, `on_floor`, `under_ceiling`, `under_floor`, `very_deep_under_floor`	`above_preliminary_surface`, `biome`, `hole`, `noise_threshold`, `not`, `steep`, `stone_depth`, `temperature`, `vertical_gradient`, `water`, `y_above`
`worldgen/material_rule`	changed	`bedrock_floor`, `bedrock_roof`, `end`, `nether`, `overworld`, `overworld/biome_surface`, `overworld/biome_surface/dappled_forest`, `overworld/biome_surface/default`, `overworld/biome_surface/dripstone_caves`, `overworld/biome_surface/frozen_peaks`, `overworld/biome_surface/grove`, `overworld/biome_surface/ice_spikes`, `overworld/biome_surface/jagged_peaks`, `overworld/biome_surface/mangrove_swamp`, `overworld/biome_surface/mushroom_fields`, `overworld/biome_surface/old_growth_pine_taiga`, `overworld/biome_surface/snowy_slopes`, `overworld/biome_surface/stony_peaks`, `overworld/biome_surface/stony_shore`, `overworld/biome_surface/sulfur_caves`, `overworld/biome_surface/windswept_gravelly_hills`, `overworld/biome_surface/windswept_hills`, `overworld/biome_surface/windswept_savanna`, `overworld/gravel_or_stone_if_ceiling`, `overworld/powder_snow_surface`, `overworld/powder_snow_under_surface`, `overworld/sand_or_sandstone_if_ceiling`, `overworld/sulfur_cave_bands`, `overworld/surface`, `overworld/under_biome_surface`, `overworld/under_biome_surface/default`, `overworld/under_biome_surface/frozen_peaks`, `overworld/under_biome_surface/grove`, `overworld/under_biome_surface/jagged_peaks`, `overworld/under_biome_surface/snowy_slopes`, `overworld/under_biome_surface/windswept_gravelly_hills`, `overworld/under_biome_surface/windswept_savanna`, `overworld/underground`, `overworld_caves`, `overworld_floating_islands`	`bandlands`, `block`, `condition`, `sequence`
`worldgen/noise`	changed	`small_patch`	—
`worldgen/placed_feature`	changed	`brown_mushroom_dappled_forest`, `fallen_poplar_tree`, `orange_poplar_leaf_litter`, `patch_red_shrub`, `red_poplar_leaf_litter`, `trees_dappled_forest`, `yellow_poplar_leaf_litter`	—
`worldgen/structure`	changed	`abandoned_camp_bamboo_jungle`, `abandoned_camp_birch_forest`, `abandoned_camp_cherry_grove`, `abandoned_camp_dappled_forest`, `abandoned_camp_flower_forest`, `abandoned_camp_forest`, `abandoned_camp_meadow`, `abandoned_camp_old_growth_birch_forest`, `abandoned_camp_old_growth_pine_taiga`, `abandoned_camp_old_growth_spruce_taiga`, `abandoned_camp_pale_garden`, `abandoned_camp_savanna`, `abandoned_camp_snowy_taiga`, `abandoned_camp_sparse_jungle`, `abandoned_camp_swamp`, `abandoned_camp_taiga`, `abandoned_camp_windswept_forest`, `abandoned_camp_wooded_badlands`	—
`worldgen/structure_placement`	changed	`dimension_origin`	—
`worldgen/structure_set`	changed	`abandoned_camp`	—
`worldgen/template_pool`	changed	`abandoned_camp/camp/bamboo_jungle`, `abandoned_camp/camp/birch_forest`, `abandoned_camp/camp/cherry_grove`, `abandoned_camp/camp/dappled_forest`, `abandoned_camp/camp/flower_forest`, `abandoned_camp/camp/forest`, `abandoned_camp/camp/meadow`, `abandoned_camp/camp/old_growth_birch_forest`, `abandoned_camp/camp/old_growth_pine_taiga`, `abandoned_camp/camp/old_growth_spruce_taiga`, `abandoned_camp/camp/pale_garden`, `abandoned_camp/camp/savanna`, `abandoned_camp/camp/snowy_taiga`, `abandoned_camp/camp/sparse_jungle`, `abandoned_camp/camp/swamp`, `abandoned_camp/camp/taiga`, `abandoned_camp/camp/windswept_forest`, `abandoned_camp/camp/wooded_badlands`, `abandoned_camp/tent/bamboo_jungle`, `abandoned_camp/tent/birch_forest`, `abandoned_camp/tent/cherry_grove`, `abandoned_camp/tent/dappled_forest`, `abandoned_camp/tent/flower_forest`, `abandoned_camp/tent/forest`, `abandoned_camp/tent/meadow`, `abandoned_camp/tent/old_growth_birch_forest`, `abandoned_camp/tent/old_growth_pine_taiga`, `abandoned_camp/tent/old_growth_spruce_taiga`, `abandoned_camp/tent/pale_garden`, `abandoned_camp/tent/savanna`, `abandoned_camp/tent/snowy_taiga`, `abandoned_camp/tent/sparse_jungle`, `abandoned_camp/tent/swamp`, `abandoned_camp/tent/taiga`, `abandoned_camp/tent/windswept_forest`, `abandoned_camp/tent/wooded_badlands`	—
`worldgen/tree_decorator_type`	changed	`shelf_mushroom`	—
`worldgen/trunk_placer_type`	changed	`poplar_trunk_placer`	—

The official notes

Read the 26.3 Snapshot 1 article on minecraft.net.

That article's technical changes are grouped under these headings — open it for the detail:

Minecraft Server Management Protocol 3.1.0
Data Pack Version 108.0
Commands
Data Components
Trim Materials
Instruments
Block Entity Data
Slot Sources
Loot Functions
World Generation
Tags
Particles
Resource Pack Version 89.0
Palette Textures
Equipment Assets
Block Sprites
Item Sprites
UI Sprites
Entity Textures
Sounds
Particles

Minecraft Wiki page for 26.3-snapshot-1.

In the journal

← 26.2 · All builds · 26.3-snapshot-2 →

Sources

misode/mcmeta — 26.3-snapshot-1 summary — formats and registries, generated from the game’s own data.
minecraft.net — 26.3 Snapshot 1 — section names only.