HTC really wants to make a cool transparent case for its flagship devices. It started with the One M8 and the "Dot View" case, which adapted the windowed covers first released by Samsung and LG into a grid with Lite Brite-style holes to view the screen underneath. There was a revised Dot View case for the One M9, but for the new HTC 10, we're getting a redesigned and completely transparent "Ice View" case. Like the previous iterations, HTC has released a specialized app in the Play Store to let users operate the case.
According to the description, users can view the time, date, weather, and battery level without opening the case, answer calls (there's a handy cutout for the earpiece), dismiss alarms, review notifications, and operate basic controls. It's all fairly standard stuff, and most of it's covered by other manufacturers either with their own windowed cases or various takes on an ambient display mode. There's also a dual-finger gesture for opening the camera app.
The Ice View app is free, but of course it only works on the HTC 10, and you need the case itself to do anything with it. That will be a hefty $50 on top of your brand new phone, please.