It runs right here, in your browser. It asks for your camera before it uses it, and nothing leaves your device.

Your front camera becomes the view through a rainy window. Rain runs down the glass, the world outside is soft and blurred behind it, and you wipe a clear streak by waving your hand at the camera, or with your finger or mouse - which slowly fogs back up. Nothing is recorded or leaves your device.

The wipe is a mask on the glass, and it fogs back over about fifteen seconds from clear to full - long enough to look through, short enough that you wipe again.
The rain is heard as well as seen: filtered noise, shaped into rainfall with Web Audio. R makes the rain heavier, C wipes the whole window, H hides the interface.
If there is no camera, or it is refused, the window looks out on a rainy night street instead, so the experience never stops at a permission prompt.
