cldr-localenames-full/main/gv/territories.json

Translated versions of locale display name elements: languages, scripts, territories, and variants. (all locales)

{
  "main": {
    "gv": {
      "identity": {
        "version": {
          "_cldrVersion": "44.1"
        },
        "language": "gv"
      },
      "localeDisplayNames": {
        "territories": {
          "GB": "Rywvaneth Unys",
          "GB-alt-short": "Rywvaneth Unys",
          "IM": "Ellan Vannin"
        }
      }
    }
  }
}