Examine source code of Youtube Auto-Subscriber

{
  "manifest_version": 2,
  "name": "Youtube Auto-Subscriber",
  "description": "A Youtube Clicker",
  "version": "1.0",
  "permissions": [
    "storage",
    "tabs",
    "activeTab",
    "alarms"
  ],
  "icons": {
    "16": "/images/ytas48.png",
    "48": "/images/ytas48.png",
    "128": "/images/ytas128.png"
  },
  "background": {
    "scripts": [
      "background.js"
    ],
    "persistent": true
  },
  "browser_action": {
    "browser_style": true,
    "default_icon": {
      "16": "/images/ytas48.png",
      "32": "/images/ytas48.png"
    },
    "default_title": "Youtube Auto-Subscriber",
    "default_popup": "popup/popup.html"
  },
  "content_scripts": [
    {
      "js": [
        "jquery.min.js",
        "content.js"
      ],
      "matches": [
        "*://*.youtube.com/*"
      ]
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{f871e4a6-989d-4701-82be-55d4d12a5c6a}"
    }
  }
}