Examine source code of Translator

{
  "manifest_version": 2,
  "name": "Translator",
  "description": "Add a context menu option to selections to translate the selection.",
  "version": "0.0.4",
  "homepage_url": "https://github.com/Gemorroj/extension-translator",
  "applications": {
    "gecko": {
      "strict_min_version": "57.0a1",
      "id": "{ad2b7d9f-0f45-4435-bca9-90df7adcd5ed}"
    }
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "icons": {
    "16": "favicon.png",
    "32": "favicon.png",
    "48": "favicon.png"
  },
  "permissions": [
    "notifications",
    "contextMenus",
    "storage"
  ],
  "options_ui": {
    "page": "options.html"
  }
}