Examine source code of YouTube elements

{
  "manifest_version": 2,
  "name": "YouTube elements",
  "description": "This extension make all click elements make very visible",
  "version": "1.1",
  "icons": {
    "128": "icon128.png"
  },
  "browser_action": {
    "default_icon": "icon.png",
    "default_title": "YouTube elements"
  },
  "permissions": [
    "activeTab",
    "tabs"
  ],
  "content_scripts": [
    {
      "all_frames": true,
      "matches": [
        "https://youtube.com/*",
        "https://www.youtube.com/*"
      ],
      "js": [
        "content_scripts.js"
      ],
      "run_at": "document_end"
    }
  ]
}