Examine source code of Super YouTube Theme Maker

{
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "content_scripts": [
    {
      "js": [
        "jquery.js",
        "client.js"
      ],
      "run_at": "document_start",
      "matches": [
        "https://www.youtube.com/*"
      ]
    }
  ],
  "description": "Change YouTube™ colors to whatever you like. Make thousands of themes by yourself. Start to have fun!",
  "icons": {
    "16": "128.png",
    "48": "128.png",
    "128": "128.png"
  },
  "manifest_version": 2,
  "name": "Super YouTube™ Theme Maker",
  "version": "1.0.4resigned1",
  "browser_specific_settings": {
    "gecko": {
      "id": "@superthememakerforyoutube"
    }
  }
}