Java Edition:Light (Item)

Light is an item normally only obtainable through commands or the operator tab in the creative menu. The light item was obtainable in the April Fools' snapshots 22w13oneBlockAtATime and 23w13a_or_b. The light item can be placed to create the light block. It can have different BlockStateTags for it's light level and whether it's waterlogged.

Obtaining

22w13oneBlockAtATime Endermen Spawning

Warning: April Fools'

This feature requires April Fools' versions which may require file renaming or file deletion to load. See the Loading April Fools' Versions tutorial for more information.

Endermen in the April Fools' version 22w13oneBlockAtATime spawn carrying random blocks. One of these blocks they can spawn with is light. There are 902 different blocks that are equally likely for them to spawn with and so there is a 1/902 = 0.11% chance of the enderman spawning with this block specifically. If the enderman spawns holding a generic_item_block (1/902) there's also a 1/1105 chance it will be this block as its block state, but there's only a 0.0001% chance of this occurring.^[1]

In the version, the block can be received from the enderman by angering it then letting it attack the player with an open hand. This will cause the block to transfer into the player's hand. Also, if the enderman dies and the falling block launches from the enderman, this can be picked up by the player. The items can be stored in 22w13oneBlockAtATime by switching the block from carrying to the offhand, shift right-clicking onto a donkey/mule with a chest, and then swapping the item into a slot. Additionally, the enderman carrying the block can be updated and then killed in a later version to obtain the item.

23w13a_or_b Votes

Warning: April Fools'

This feature requires April Fools' versions which may require file renaming or file deletion to load. See the Loading April Fools' Versions tutorial for more information.

The April Fool's snapshot 23w13a_or_b introduces a plethora of ways to obtain every block and item in the game, including the light item. These include:

The egg_free vote, when applied, will allow chickens to lay any block or item in the game (without NBT). This means all chickens have the chance of laying the light item.
The give_item vote, when applied, will give every online player a random amount of any block or item in the game (without NBT), meaning that you could have the light item randomly given to you.
The fish_anything vote, when applied, will allow any item from the creative menu (not the operator tab, with NBT) to be fished (combine with the buff_fishing vote to greatly increase fishing speed). What this means is that there is a chance that the light item can be randomly fished.
The replace_items vote, when applied, will replace all items in online players' inventories with any block or item in the game (NBT of the original replaced item is preserved). This allows for the light item with any NBT.
The replace_loot_drop vote, when applied, will replace all loot drops of a random block or item with any block or item in the game (if the original item that is being dropped has NBT, it will be preserved). This is also another method for the light item with any NBT.
The replace_recipe_output vote, when applied, will replace all recipes for the given item with any block or item in the game (NBT is preserved if the original output item is supposed to have NBT.) This is yet another method for the light item with any NBT.
The villager_gem vote, when applied, will replace all emeralds in all loaded villager's trades with any block or item in the game (without NBT). This means that you can get a villager that trades the light item, allowing for infinite amounts of the light item.
The basalt_gen_replace, cobblestone_gen_replace, obsidian_gen_replace, and stone_gen_replace votes, when applied, replace the block of their respective fluid interaction with any block in the game, allowing for blocks in invalid positions and the placement of operator-only blocks such as the command block.

Notes

↑ 1/902 * 1/1105 ≈ 0.0001%

[1] 1/902 * 1/1105 ≈ 0.0001%

[1]