cldr-localenames-full/main/szl/languages.json

Translated versions of locale display name elements: languages, scripts, territories, and variants.

{
  "main": {
    "szl": {
      "identity": {
        "language": "szl"
      },
      "localeDisplayNames": {
        "languages": {
          "en": "angelski",
          "szl": "ślōnski"
        }
      }
    }
  }
}