Examine source code of Varia Integrator

{
  "name": "Varia Integrator",
  "description": "Route all downloads to Varia if it's running.",
  "version": "1.5.4",
  "icons": {
    "16": "icon16.png",
    "48": "icon48.png",
    "128": "icon128.png"
  },
  "action": {
    "default_popup": "popup.html"
  },
  "permissions": [
    "downloads",
    "storage",
    "<all_urls>",
    "tabs",
    "cookies"
  ],
  "manifest_version": 3,
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "giantpinkrobots@protonmail.com"
    }
  }
}