Vanillabean makes some updates to how Elytra are obtained, to make them more reasonable in multiplayer environments.
When you locate an End City (which can be done using Eyes of Ender in Vanillabean), Elytra can be obtained from the End City's ship - as it can be in regular Minecraft.
An End Ship's room contains three Elytra Vaults, and an item frame with a Final Key inside. This Final Key can be used to unlock any one of the three Elytra Vaults. An Elytra is guaranteed from the middle one, and a rare prize is guaranteed from either of the two outer Elytra Vaults.
Like with regular Vaults, each player may only use an Elytra Vault once. Players can obtain Final Keys through the Settlement structure, which may allow multiple players to get an Elytra from the same End City.
Additional Final Keys can also be used to open the other Elytra Vaults, giving you some incentive to revisit End Cities later on.
All three Elytra Vaults will drop 3 common rewards from the following list:
2-3 Diamonds
4-8 Iron Ingots
2-7 Gold Ingots
2-6 Emeralds
1-10 Beetroot Seeds
1 Diamond Sword (Enchanted with XP level equivalent of 20-39)
1 Diamond Boots (Enchanted with XP level equivalent of 20-39)
1 Diamond Chestplate (Enchanted with XP level equivalent of 20-39)
1 Diamond Leggings (Enchanted with XP level equivalent of 20-39)
1 Diamond Helmet (Enchanted with XP level equivalent of 20-39)
1 Diamond Pickaxe (Enchanted with XP level equivalent of 20-39)
1 Diamond Shovel (Enchanted with XP level equivalent of 20-39)
The two Elytra Vaults that don't give an Elytra will give a rare reward instead. This is randomly selected from the following list:
2-3 Spire Armor Trim Smithing Templates
2-3 Eye Armor Trim Smithing Templates
1 Enderman Soul (see Mob Souls)
1 Music Disc (Tall) (see Custom Discs)
1 Enchanted Book (Antigravity) (see Enchantments)