Examine source code of YouTube Speed Tweak

{
  "manifest_version": 2,
  "name": "YouTube Speed Tweak",
  "version": "1.1",
  "description": "Increases YouTube playback speed up to 5x using the standard keyboard shortcuts.",
  "icons": {
    "48": "icons/speedtweak-icon-48.png",
    "128": "icons/speedtweak-icon-128.png"
  },
  "permissions": [
    "activeTab"
  ],
  "content_scripts": [
    {
      "matches": [
        "https://www.youtube.com/*"
      ],
      "js": [
        "content.js"
      ]
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{34786782-f90a-4173-9085-77729ba5896a}"
    }
  }
}