zh_tw-Lang-Pack-1.12v21 is a release file of the Minecraft resource pack Mods - Traditional Chinese Localization Resource Package, made for Minecraft 1.12.2. It was published on January 8, 2022 and is 12 MB in size. For the full description, screenshots and every other version, visit the Mods - Traditional Chinese Localization Resource Package resource pack page.
How to install: Put the .zip into .minecraft/resourcepacks (do not extract it) and enable it under Options → Resource Packs.