What proxy is 'automatically detect settings' actually giving me?

Chrome doesn't seem to like the 'automatically detect settings' (at least not where I am right now), so I have to change over to have an explicitly configured proxy.

But what to enter? PowerShell to the rescue:

[System.Net.WebRequest]::DefaultWebProxy.GetProxy("http://www.test.com")

...tells you what proxy the system will use for the uri provided, and that's pretty much the only one you ever have to worry about.