Examine source code of -1 proxy

{
  "manifest_version": 2,
  "name": "Proxy Extension",
  "version": "3.0.2",
  "description": "Proxy Extension for Firefox",
  "permissions": [
    "proxy",
    "activeTab",
    "storage",
    "<all_urls>",
    "dns",
    "alarms"
  ],
  "browser_specific_settings": {
    "gecko": {
      "strict_min_version": "91.1.0",
      "id": "{c9bb9a4b-60fd-4f1d-8602-bfa4a43c04b6}"
    }
  },
  "background": {
    "scripts": [
      "background.js",
      "js-yaml.min.js"
    ],
    "persistent": false
  },
  "browser_action": {
    "default_popup": "popup.html",
    "default_icon": {
      "16": "icon.png",
      "48": "icon.png",
      "128": "icon.png"
    }
  }
}