Examine source code of Text-to-Speech Reader

{
  "manifest_version": 2,
  "name": "Text-to-Speech Reader",
  "version": "1.0",
  "description": "Convert selected text into speech.",
  "browser_action": {
    "default_popup": "popup.html",
    "default_title": "Text-to-Speech Reader"
  },
  "permissions": [
    "activeTab"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{8734a34b-2d2b-4df8-92d5-2ff4d94f6f53}"
    }
  }
}