Examine source code of LocalSync

{
  "manifest_version": 3,
  "name": "LocalSync",
  "version": "1.0.1",
  "description": "Sync localStorage data between different environments with ease.",
  "permissions": [
    "scripting",
    "tabs",
    "storage"
  ],
  "host_permissions": [
    "<all_urls>"
  ],
  "action": {
    "default_title": "Sync localStorage between environments",
    "default_popup": "popup.html"
  },
  "icons": {
    "16": "icons/icon-16.png",
    "32": "icons/icon-32.png",
    "48": "icons/icon-48.png",
    "128": "icons/icon-128.png"
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "localsync@sync.local",
      "strict_min_version": "142.0",
      "data_collection_permissions": {
        "required": [
          "none"
        ],
        "optional": [
          "technicalAndInteraction"
        ]
      }
    }
  }
}