Examine source code of FocusGuard Pro

{
  "manifest_version": 3,
  "name": "FocusGuard Pro",
  "version": "2.1",
  "description": "Control fullscreen and visibility detection per site.",
  "icons": {
    "16": "icon.png",
    "48": "icon.png",
    "128": "icon.png"
  },
  "permissions": [
    "storage"
  ],
  "host_permissions": [
    "<all_urls>"
  ],
  "action": {
    "default_popup": "popup.html"
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "content.js"
      ],
      "run_at": "document_start",
      "all_frames": true
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "@focusguard",
      "strict_min_version": "58.0",
      "data_collection_permissions": {
        "required": [
          "websiteActivity",
          "websiteContent"
        ]
      }
    }
  }
}