Examine source code of Rumble toolkit

{
  "manifest_version": 2,
  "name": "__MSG_extName__",
  "description": "__MSG_extDescription__",
  "version": "1.1.0",
  "default_locale": "en",
  "browser_specific_settings": {
    "gecko": {
      "id": "willemarf@gmail.com",
      "strict_min_version": "99.0"
    }
  },
  "author": "Wiskton",
  "icons": {
    "16": "icons/rumble-16.png",
    "32": "icons/rumble-32.png",
    "64": "icons/rumble-64.png",
    "128": "icons/rumble-128.png"
  },
  "background": {
    "scripts": [
      "js/common.js",
      "js/background.js"
    ]
  },
  "browser_action": {
    "browser_style": true,
    "default_icon": {
      "16": "icons/rumble-16.png",
      "32": "icons/rumble-32.png",
      "64": "icons/rumble-64.png",
      "128": "icons/rumble-128.png"
    },
    "default_title": "Rumble",
    "default_popup": "index.html"
  },
  "content_scripts": [
    {
      "matches": [
        "http://rumble.com/*",
        "https://rumble.com/*"
      ],
      "js": [
        "js/common.js",
        "js/inject.js"
      ]
    }
  ],
  "permissions": [
    "storage",
    "downloads"
  ]
}