Examine source code of Word Reference Translator

{
  "manifest_version": 2,
  "name": "WordReference Translator",
  "version": "1.0.7",
  "author": "Sebastián Passaro",
  "description": "Firefox extension to allow quick access to www.wordreference.com. Based on https://addons.mozilla.org/es/firefox/addon/wordreference-translator/ (currently obsolete).",
  "homepage_url": "https://github.com/spassarop/wrtranslator/tree/master",
  "icons": {
    "48": "icons/wr-icon-48.ico"
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "wrtranslator.js"
      ],
      "css": [
        "wrtranslator.css"
      ]
    }
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "browser_action": {
    "browser_style": true,
    "default_icon": "icons/wr-icon-48.ico",
    "default_title": "www.wordreference.com"
  },
  "options_ui": {
    "page": "options.html"
  },
  "permissions": [
    "storage",
    "menus"
  ],
  "default_locale": "en"
}