Examine source code of YouTube Yeller

{
  "manifest_version": 2,
  "name": "YouTube Yeller",
  "version": "1.0",
  "description": "Stops youtube addiction by yelling at you for navigating to the site",
  "icons": {
    "48": "icons/yt-yell-48.png"
  },
  "content_scripts": [
    {
      "matches": [
        "*://*.youtube.com/*"
      ],
      "js": [
        "yt-yell.js"
      ]
    }
  ],
  "web_accessible_resources": [
    "yell.mp3"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{ad248a33-af97-408b-a360-5db93c75f507}"
    }
  }
}