Examine source code of Feed Killer

{
  "name": "Feed-killer",
  "author": "Serhii Tatsiak",
  "version": "0.5",
  "content_scripts": [
    {
      "matches": [
        "*://*.youtube.com/*"
      ],
      "css": [
        "style.css"
      ],
      "js": [
        "content.js"
      ],
      "run_at": "document_start"
    }
  ],
  "browser_action": {},
  "description": "Browser extension that removes distracting elements from Youtube™",
  "manifest_version": 2
}