Examine source code of Read-Aloud Preview GM

{
  "manifest_version": 2,
  "name": "Read-Aloud Preview",
  "version": "1.3",
  "description": "Preview how your text sounds using text-to-speech.",
  "permissions": [],
  "browser_action": {
    "default_title": "Read-Aloud Preview",
    "default_popup": "popup.html"
  },
  "icons": {
    "32": "icons/logo_32.png",
    "64": "icons/logo_64.png",
    "128": "icons/logo_128.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "@Read-Aloud-Preview",
      "data_collection_permissions": {
        "required": [
          "locationInfo"
        ],
        "optional": [
          "technicalAndInteraction"
        ]
      }
    }
  }
}