server1.21/config/carpettisaddition/mapping/yarn_version.json

[
  {
    "minecraftVersion": "1.18.2",
    "yarnVersion": "1.18.2+build.4"
  },
  {
    "minecraftVersion": "1.20.1",
    "yarnVersion": "1.20.1+build.10"
  },
  {
    "minecraftVersion": "1.21",
    "yarnVersion": "1.21+build.2"
  }
]