For example, I just started casting music to it, and because it has wake on LAN (MiBox S doesn't..) it turned my tv on, and then I was able to use the volume buttons on my phone and that command went to the Shield, which sent it to the remote which sent an IR command to my sonos soundbar to control that. I was very impressed the first time this happened
It's there since 2015 model.
However it's not wakeup. I don't inside detail of hardware architecture. But even though Shield "sleeps", apps run in background. Like downloading service.