Examine source code of Google Docs Overlay

{
  "manifest_version": 3,
  "name": "Google Docs Overlay",
  "version": "1.0",
  "browser_specific_settings": {
    "gecko": {
      "id": "@GoogleDocsOverLay",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      },
      "strict_min_version": "59.0"
    }
  },
  "permissions": [
    "storage",
    "tabs"
  ],
  "host_permissions": [
    "https://docs.google.com/*"
  ],
  "content_scripts": [
    {
      "matches": [
        "https://docs.google.com/document/*"
      ],
      "js": [
        "content.js"
      ]
    }
  ],
  "icons": {
    "48": "icons/icon48.png",
    "128": "icons/icon128.png"
  },
  "action": {
    "default_popup": "popup.html"
  }
}