Examine source code of YTcleaner

{
  "manifest_version": 2,
  "name": "YTcleaner",
  "version": "0.1",
  "description": "Cleans your youtube ;)",
  "icons": {
    "128": "icon.svg"
  },
  "content_scripts": [
    {
      "matches": [
        "*://*.youtube.com/*"
      ],
      "js": [
        "cleaner.js"
      ],
      "css": [
        "cleaner.css"
      ]
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{12813f06-ed29-4a23-b06c-91e5aa462c9b}"
    }
  }
}