curl --request GET \
  --url https://api.deepl.com/v3/languages/resources \
  --header 'Authorization: <api-key>'

[
  {
    "name": "translate_text",
    "features": [
      {
        "name": "formality",
        "needs_target_support": true
      },
      {
        "name": "style_rules",
        "needs_target_support": true
      },
      {
        "name": "tag_handling",
        "needs_source_support": true,
        "needs_target_support": true
      },
      {
        "name": "glossary",
        "needs_source_support": true,
        "needs_target_support": true
      },
      {
        "name": "auto_detection",
        "needs_source_support": true
      }
    ]
  },
  {
    "name": "voice",
    "features": [
      {
        "name": "glossary",
        "needs_source_support": true,
        "needs_target_support": true
      }
    ]
  },
  {
    "name": "style_rules",
    "features": []
  }
]

{
  "message": "<string>",
  "code": "invalid_content_type"
}

{
  "message": "<string>",
  "code": "invalid_content_type"
}

{
  "message": "<string>",
  "code": "invalid_content_type"
}

{
  "message": "<string>",
  "code": "invalid_content_type"
}