Examine source code of Set Proxy

{
  "manifest_version": 2,
  "name": "Set Proxy",
  "description": "Add multiple proxies (SOCKS5/HTTP/HTTPS), select one, switch ON/OFF.",
  "version": "1.4",
  "permissions": [
    "proxy",
    "storage",
    "<all_urls>"
  ],
  "icons": {
    "16": "icons/icon-off-16.png",
    "32": "icons/icon-off-32.png",
    "48": "icons/icon-off-48.png",
    "96": "icons/icon-off-96.png",
    "128": "icons/icon-off-128.png"
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "browser_action": {
    "default_popup": "popup.html",
    "default_title": "Set Proxy",
    "default_icon": {
      "16": "icons/icon-off-16.png",
      "32": "icons/icon-off-32.png"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "set-proxy@local.ext",
      "strict_min_version": "140.0",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    },
    "gecko_android": {
      "strict_min_version": "142.0"
    }
  }
}