Examine source code of Related-B-Gone

{
  "manifest_version": 2,
  "name": "Related-B-Gone",
  "version": "1.0",
  "description": "Removes related videos and chats from youtube via CSS",
  "content_scripts": [
    {
      "matches": [
        "*://*.youtube.com/*"
      ],
      "js": [
        "relatedBgone.js"
      ]
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{d470e083-33f5-4bae-8ec5-9e93a1d1736d}"
    }
  }
}