christmas2021.zip is an alpha file of the Minecraft resource pack Christmas Music Sound Pack!, made for Minecraft 1.17. It was published on November 10, 2021 and is 49.1 MB in size. Pre-release builds can contain bugs — back up your world before installing. For the full description, screenshots and every other version, visit the Christmas Music Sound Pack! resource pack page.
How to install: Put the .zip into .minecraft/resourcepacks (do not extract it) and enable it under Options → Resource Packs.