[
  {
    "namespace": "manifest",
    "types": [
      {
        "$extend": "OptionalPermission",
        "choices": [
          {
            "type": "string",
            "enum": ["messengerSettings"]
          }
        ]
      }
    ]
  },
  {
    "namespace": "messengerSettings",
    "description": "The messengerSettings API allows to access global messenger settings.",
    "permissions": ["messengerSettings"],
    "properties": {
      "messagePlainTextFlowedOutputEnabled": {
        "$ref": "types.Setting",
        "description": "Whether long lines in outgoing plain text messages will get soft line breaks (<var> \n</var>) or hard line breaks (<var>\n</var>), to comply with requirements from RFC 2822. Soft line breaks will be ignored when displayed by the receiving client. When flowed output is enabled, add-ons should not create plain text messages with manually inserted hard or soft line breaks to achieve a certain text width, as that will most probably interfere with the default line break handling and generate ridged text. When flowed output is disabled, add-ons could add hard line breaks to have control over the final message, but any line longer than the maximum line length will still receive additional hard line breaks. See $(ref:messengerSettings.messageLineLengthLimit)."
      },
      "messageLineLengthLimit": {
        "$ref": "types.Setting",
        "description": "The line length limit for outgoing messages, to comply with requirements from RFC 2822. See description of $(ref:messengerSettings.messagePlainTextFlowedOutputEnabled)."
      }
    }
  }
]