Examine source code of SkillChecker

{
  "manifest_version": 3,
  "name": "SkillChecker",
  "version": "1.1",
  "description": "A skillcheck to stop you being terminally online.",
  "permissions": [
    "storage"
  ],
  "icons": {
    "16": "icons/SkillChecker-16.png",
    "32": "icons/SkillChecker-32.png",
    "48": "icons/SkillChecker-48.png",
    "96": "icons/SkillChecker-96.png",
    "128": "icons/SkillChecker-128.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "SkillChecker@Bee",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    }
  },
  "action": {
    "default_icon": "icons/SkillChecker-48.png",
    "default_title": "SkillChecker",
    "default_popup": "popup/timer.html"
  },
  "content_scripts": [
    {
      "matches": [
        "*://*.youtube.com/*",
        "*://x.com/*",
        "*://*.crunchyroll.com/*",
        "*://*.instagram.com/*",
        "*://*.reddit.com/*",
        "*://*.tiktok.com/*",
        "*://*.primevideo.com/*",
        "*://*.netflix.com/*",
        "*://bsky.app/*",
        "*://*.pinterest.com/*",
        "*://discord.com/*",
        "*://*.threads.com/*"
      ],
      "js": [
        "SkillChecker.js"
      ],
      "run_at": "document_idle"
    }
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "web_accessible_resources": [
    {
      "resources": [
        "skillcheck.js"
      ],
      "matches": [
        "*://*.youtube.com/*",
        "*://x.com/*",
        "*://*.crunchyroll.com/*",
        "*://*.instagram.com/*",
        "*://*.reddit.com/*",
        "*://*.tiktok.com/*",
        "*://*.primevideo.com/*",
        "*://*.netflix.com/*",
        "*://bsky.app/*",
        "*://*.pinterest.com/*",
        "*://discord.com/*",
        "*://*.threads.com/*"
      ]
    }
  ]
}