resource pack is based on the server A Minecraft Movie Live Event many elements of the ordinary world have been changed

Feathered Elytra – Replaces the default Elytra with a light, feathery design, making them look like majestic bird wings.

Iron Elytra – Replaces the default Elytra with a sturdy iron version, giving them a sleek metallic look.

dyes update in 1.21.9