Examine source code of YT Time Limiter

{
  "manifest_version": 2,
  "name": "YT Time Limiter",
  "version": "3.0",
  "description": "Limits weekly time spent on YouTube",
  "browser_specific_settings": {
    "gecko": {
      "id": "{8188ed5c-fab3-4f55-a64b-9bf5089f41c5}"
    },
    "gecko_android": {
      "strict_min_version": "120.0"
    }
  },
  "icons": {
    "512": "icon.png"
  },
  "browser_action": {
    "default_popup": "popup/index.html",
    "default_title": "YT Time Limiter"
  },
  "permissions": [
    "storage"
  ],
  "content_scripts": [
    {
      "matches": [
        "*://*.youtube.com/*"
      ],
      "js": [
        "content.js"
      ]
    }
  ]
}