Examine source code of Plain Translate

{
  "author": "igorlogius",
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "browser_action": {
    "default_area": "navbar",
    "default_popup": "popup.html"
  },
  "commands": {
    "_execute_browser_action": {}
  },
  "default_locale": "en",
  "description": "__MSG_addonDesc__",
  "homepage_url": "https://github.com/igorlogius/plain-translate",
  "icons": {
    "64": "icon.png"
  },
  "manifest_version": 2,
  "name": "__MSG_addonName__",
  "permissions": [
    "activeTab",
    "menus",
    "storage"
  ],
  "version": "2.1.7",
  "browser_specific_settings": {
    "gecko": {
      "id": "{4aee219e-fbc1-4fdc-a58c-8fe27c3828f8}"
    }
  }
}