Examine source code of Youtube Red Bar

{
  "manifest_version": 2,
  "name": "Youtube Red Bar",
  "version": "1.7",
  "description": "Change that youtube's bar to bring the full red back",
  "permissions": [],
  "icons": {
    "48": "icons/icon-48.png",
    "64": "icons/icon-64.png",
    "128": "icons/icon-128.png"
  },
  "content_scripts": [
    {
      "matches": [
        "https://*.youtube.com/*"
      ],
      "js": [
        "YTRB_Extension.js"
      ]
    }
  ],
  "web_accessible_resources": [
    "YTRB_Style.css"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{071cae93-20ed-4dd1-a7c0-2ac7e1766e67}"
    }
  }
}