Does the extension detect the device and show AMP? Is there a setting?

Does the extension detect the device and show AMP? Is there a setting?

That's correct, the AMP view is displayed for those browsing from mobile devices. There are two variants of module setup: force a customer to stay on the AMP version when browsing from a mobile, or redirect to AMP only from Google SERP. This can be configured from the extension's general settings: