Switching to WebExtension some features of the MM3-ProxySwitch are missing. Many users asked for it, including the feature "Automatic switching" (testUrl).

This feature is now implemented. This requires the possibility to check a URL for accessibility. This is implemented via a "HEAD" request to the server.

We documented this in two sections:
New: https://Proxy-Offline-Browser.com/ProxySwitch/News.html#2018.332

Requested Permissions: https://Proxy-Offline-Browser.com/ProxySwitch/#Download