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

{
  "style_rules": [
    {
      "style_id": "bd0a38f3-1831-440b-a8dd-2c702e2325ab",
      "name": "<string>",
      "creation_time": "2023-11-07T05:31:56Z",
      "updated_time": "2023-11-07T05:31:56Z",
      "language": "ar",
      "version": 13,
      "configured_rules": {
        "style_and_tone": {
          "abbreviations": "use_abbreviations_and_symbols",
          "short_vs_long_words": "use_short_words"
        },
        "punctuation": {
          "apostrophe": "use_curly_apostrophes"
        }
      },
      "custom_instructions": [
        {
          "id": "68fdb803-c013-4e67-b62e-1aad0ab519cd",
          "label": "Currency custom instruction",
          "prompt": "Have currency symbols before the numerical value (e.g. $100, €100)",
          "source_language": "en"
        }
      ]
    }
  ]
}

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

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

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

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

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

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