Snapshot 21w13+

Snapshot 21w13+ is an April Fool's joke snapshot, supposedly the first and only snapshot for the "Update Nova-0518", released on April 1, 2021. It adds the ability to modify the game's code, as well as many features returning from 20w14infinite.
21w13+ is a fork of Minecraft 1.17 Pre-Release 1, which was not the latest snapshot when 21w13+ was released, but it was the latest snapshot when development of Snapshot 21w13+ began.
== Additions ==
=== Blocks ===
Cursor
* Returning from 20w14infinite.
* Has a namespaced ID of "minecraft:cursor".
* Can be obtained by right-clicking a dragon egg with bonemeal while holding charcoal in the offhand, wearing an elytra in the chestplate slot and gold boots in the boots slot, and under Strength, Poison, and Slow Falling effects.
* Can be found in the creative inventory.
Dragon's Heart
* Has no ingame texture, so shows as a magenta and black checkerboard texture.
* Has a namespaced ID of "minecraft:invalid".
* Cannot be found in the creative inventory.
* Can be obtained by right-clicking a dragon egg with bonemeal while under the Wither effect (but no other effects), having no armor on, and holding Nether sprouts in the offhand.
* When right-clicked with a blackstone shard on a stick while under the Weakness effect, opens an interface with 16 pages, each of which contains 16 input fields with 256 characters in each one, and "Done" and "Cancel" buttons.
* Changing the data in the input fields and clicking "Done" can modify ingame behavior.
* The exact data being shown in the fields depend on where in a chunk the block is located.
* ASCII control characters are shown in the input fields.
* "Done" cannot be clicked unless all of the 256 input fields contain exactly 256 characters and no non-ASCII characters.
Netherite stairs
* Returning from 20w14infinite.
* Has a namespaced ID of "minecraft:netherite_stairs".
* Can be obtained by right-clicking a dragon egg with bonemeal while holding a scute in the offhand, having no armor on, and under the Absorption, Fire Resistance, Hero of the Village, and Haste status effects.
=== Items ===
Blackstone Shard
* Has a namespaced ID of "minecraft:blackstone_shard"
* 9 blackstone shards can be crafted from or into 1 blackstone block.
* Can be obtained through bartering.
* Can be obtained by right-clicking a dragon egg with bonemeal while having nothing in your offhand, wearing a leather helmet on the helmet slot and netherite leggings on the leggings slot, and under Water Breathing, Absorption, Fire Resistance, and Nausea effects.
* Can be crafted with a fishing rod into a blackstone shard on a stick.
Blackstone Shard on a Stick
* Has a namespaced ID of "minecraft:blackstone_shard_on_a_stick".
* Crafted from a fishing rod and a blackstone shard.
* Cannot be obtained through right-clicking a dragon egg with bonemeal.
* Can be used to open the interface of the dragon's heart.
Emerald paste
*Obtained by smelting emeralds.
*Cannot be found in the creative inventory, and anything pertaining to them are hidden from command auto-completes.
* Can be brewed with a mundane potion into a potion of invisibility.
*Villagers will try to avoid players holding emerald paste, dropped emerald paste, or emerald paste in an item frame.
*The player loses 1 popularity for every 20 seconds holding this item within a village.
Potions
*The potion of invisibility's recipe has changed, and it is now brewed with emerald paste and a mundane potion.
*Added the potion of blindness, which now holds the original recipe of the potion of invisibility. It gives the player Blindness for 1:30, and can be extended with redstone to 4:00.
Footprint
* Returning from 20w14infinite.
* Has a namespaced ID of "minecraft:footprint".
* Can be found in the creative inventory.
* Can be obtained by right-clicking a dragon egg with bonemeal while holding a lava bucket in the offhand, wearing a creeper head in the helmet slot, a gold chestplate in the chestplate slots, nothing in the leggings slots, and diamond boots in the boots slot, and under the Regeneration and Blindness effects.
A Very Fine Item
* Returning from 20w14infinite.
* Has a namespaced ID of "minecraft:fine_item".
* Can be found in the creative inventory.
* Can be obtained by right-clicking a dragon egg with bonemeal while holding a warped fence gate in the offhand, wearing iron boots in the boots slot, and under the Absorption, Fire Resistance, Resistance, Poison, Mining Fatigue, and Speed effects.
* Its texture is changed to resemble a T4 bacteriophage.
* Behaves similar to chorus fruit (can be eaten and teleports the player), but restores 2 hunger instead of 4.
== Changes ==
=== Blocks ===
Dragon egg
* Now yields various items when used while holding bonemeal in the main hand, depending on what is being held in the offhand and worn in the armor slots, as well as the player's status effects.
** The item can be anything (even command blocks or barriers) except a dragon egg or blackstone shard on a stick.
*** This is the only way to obtain many items in survival mode.
*** To obtain a command block from using bonemeal on a dragon egg, hold any potion in the offhand, wear a golden helmet in the helmet slot, an elytra in the chestplate slot, leather legging in the leggings slot, and chainmail boots in the boots slot, and have the status effects Regeneration, Hunger, Night Vision, and Slowness.
** Drops wheat seeds while holding nothing in the offhand, wearing nothing in the armor slots, and having no status effects.
** The most common drop seems to be iron nuggets. Other common drops are gold nuggets, wheat seeds, cobblestone, and iron ingots.
**The algorithm used in this feature resembles algorithms used in the encryption of data.
=== Items ===
Potions
*Changed the recipe for the potion of invisibility to emerald paste and a mundane potion.
*The original recipe is used for potions of blindness.
=== Gameplay ===
Inventory
* Creative mode inventory has been shuffled, but in a different way from 20w14infinite.
Debug mode
* Has also been shuffled, but in a different way from 20w14infinite.
=== General ===
Loading screen
* Same as 20w14infinite, including the sound.
World selection screen
* Only worlds from 21w13+ and 20w14infinite are visible.
== Trivia ==
* This snapshot has the same protocol version as 1.17 Pre-Release 1, so crossplay between the two versions is possible but may cause some issues.
*The name "Nova-0518" refers to Jeb's birthday of May 18.
* It is proposed that the data shown in the dragon's heart interface represents a section of a highly encrypted form of Minecraft's game code.
* 4,294,967,296 bytes, or just over 4 gigabytes, of data can be accessed through the dragon's heart.
* Modifications to the game's code ingame are temporary and disappear when Minecraft is relaunched.
* 20w14infinite worlds appear on the world selection screen in later versions, but 21w13+ worlds do not. 
* When a world is upgraded from 20w14infinite to 21w13+, all already generated 20w14infinite dimensions are converted to custom dimensions (and new dimensions cannot be generated), and all 20w14infinite biomes become custom biomes. Funky portals, ant blocks, zone blocks, and boxes of infinite books become obsidian slabs, brimstone, deep snow, and hardened obsidian, respectively. Cursors, netherite stairs, footprints, and fine items do not change, since they were readded in 21w13+.
* The code for netherite stairs has been found in snapshots as early as 21w09a, and netherite stairs are present as an unused feature in the release of Minecraft 1.17. The intention of this is unknown.
Category:Fan Made Updates