Examine source code of RiffIt

{
  "name": "Riffit",
  "version": "1",
  "manifest_version": 2,
  "browser_specific_settings": {
    "gecko": {
      "id": "extension1@rifftube.net",
      "strict_min_version": "42.0"
    }
  },
  "icons": {
    "48": "icons/person-48.png"
  },
  "browser_action": {
    "browser_style": true,
    "default_icon": "icons/person-32.png"
  },
  "permissions": [
    "identity",
    "notifications",
    "*://www.googleapis.com/*",
    "*://accounts.google.com/*",
    "<all_urls>",
    "tabs",
    "https://rifftube.net/*"
  ],
  "background": {
    "scripts": [
      "background/authorize.js",
      "background/userinfo.js",
      "background/main.js"
    ]
  },
  "options_ui": {
    "page": "options/options.html"
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "content.js"
      ]
    }
  ]
}