Examine source code of Proxy Manager

{
  "manifest_version": 2,
  "name": "Proxy Manager",
  "version": "3.0",
  "description": "Manage multiple proxies and toggle between them easily",
  "permissions": [
    "proxy",
    "storage",
    "<all_urls>"
  ],
  "background": {
    "scripts": [
      "background.js"
    ],
    "persistent": true
  },
  "browser_action": {
    "default_popup": "popup.html",
    "default_icon": {
      "16": "icons/icon-disabled-16.png",
      "48": "icons/icon-disabled-48.png"
    }
  },
  "icons": {
    "16": "icons/icon-disabled-16.png",
    "48": "icons/icon-disabled-48.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "strict_min_version": "142.0",
      "id": "{aec8697d-d5ad-4227-859d-45f31562d213}",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    }
  }
}