Examine source code of Proxy Switcher Simple

{
  "manifest_version": 2,
  "name": "Proxy Switcher Pro",
  "version": "1.1",
  "description": "Fast proxy change, supports filtering by country.",
  "permissions": [
    "proxy",
    "storage",
    "tabs",
    "https://www.proxy-list.download/*",
    "<all_urls>"
  ],
  "browser_action": {
    "default_popup": "popup.html",
    "default_icon": {
      "16": "icon.png"
    }
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "browser_specific_settings": {
    "gecko": {
      "strict_min_version": "91.1.0",
      "id": "{c6bf7eae-f869-4ea6-983a-73a59178a572}"
    }
  }
}