This week we are releasing a bit of a smaller snapshot. However, if you're into switching game modes and completing advancements, this is right up your alley!

Edit: We've now released 20w20b to fix a bug

Fixed Bug in 20w20b

MC-183769 NPE in server initialization

New Features in 20w20a

Added new Game Mode Switcher debug menu
Added new Nether Advancements

Game Mode Switcher

New F3 debug feature which allows you to switch game modes with traditional "tabbing" functionality.

Hold F3 and tap F4 to open the menu
Tapping F4 will cycle the game mode, or you can use the mouse
Release F3 to apply
Your last game mode is remembered and will be the first selected option, so you can quickly toggle between two game modes with a single press of F3 + F4!

F3 + N (Toggle Spectator)

A small change has been made to this debug combination.

By default, using this key would return to Creative after toggling from Spectator. It now will toggle back to the previous game mode you had.
As an example, if you were in Survival, then toggled to Spectator and back, you would be set back to Survival.

New Advancements

Hidden in the Depths unlocks when obtaining Ancient Debris
Cover Me in Debris unlocks when obtaining full Netherite armor
Country Lode, Take Me Home unlocks when using a Compass on a Lodestone
Who Is Cutting Onions? unlocks when obtaining Crying Obsidian
Not Quite "Nine" Lives unlocks when setting a Respawn Anchor to the maximum
This Boat Has Legs unlocks when riding a Strider with a Fungus on a Stick
Hot Tourist Destinations unlocks when visiting all Biomes in the Nether
Those Were the Days unlocks when entering a Bastion
War Pigs unlocks when looting a chest in a Bastion
Oh Shiny unlocks when distracting an angry Piglin with gold

Changes in 20w20a

The Bullseye advancement now unlocks when hitting the bullseye of a target block from at least 30 meters away
The Serious Dedication advancement is now awarded for obtaining a Netherite Hoe
Obtaining Blackstone now also counts for the Stone Age advancement
Breeding Striders now counts for The Parrots and the Bats and is now required for Two by Two

Technical Changes in 20w20a

Shulkers with "NoAI" can now be summoned with rotation.
Added thrown_item_picked_up_by_entity advancement trigger
Added player_generates_container_loot advancement trigger
Added item_used_on_block advancement trigger
Removed safely_harvest_honey advancement trigger

Advancements

`item_used_on_block` trigger type

Properties:

item matches the thrown item which was picked up
entity matches the entity which picked up the item

`player_generates_container_loot` trigger type

Properties:

loot_table matches the resource location of the generated loot table

`item_used_on_block` trigger type

Properties:

location matches the location at the center of the block the item was used on
item matches the item used on the block

Miscellaneous trigger changes

location got a new property smokey which checks if the location is closely above a campfire
entity_properties got new properties vehicle and targetedEntity which match the vehicle or the entity targeted by a mob

Fixed bugs in 20w20a

MC-182967 Throwing ender pearl whilst mounted doesn't teleport you
MC-179481 Structure block offset can't be bigger than 32
MC-175992 Striders are not part of the "Two by Two" advancement challenge
MC-173756 Ice Bucket Challenge advancement can be obtained by collecting obsidian from bartering
MC-173207 Bullseye advancement can be made when using a non-arrow projectile, even though the description explicitly mentions arrows
MC-118234 Advancement 'Not Today, Thank You' can be triggered by non-arrow projectiles

Fixed Bug in 20w20b

New Features in 20w20a

Game Mode Switcher

F3 + N (Toggle Spectator)

New Advancements

Changes in 20w20a

Technical Changes in 20w20a

Advancements

item_used_on_block trigger type

player_generates_container_loot trigger type

item_used_on_block trigger type

Miscellaneous trigger changes

Fixed bugs in 20w20a

`item_used_on_block` trigger type

`player_generates_container_loot` trigger type

`item_used_on_block` trigger type

Minecraft Snapshot 20w20b