You can see a public example at Luna Oaks Galleria Mall, Luna (135, 131, 22) - General > Here, a road goes down into an underwater tunnel. From outside and above the WES you cannot sea the water surface BUT the WES hides any avatar that is underwater (you just see their overhead username) and also hides some prims along the tunnel below, specially the prims farther along. If you move your camera into the WES (shown in green color when transparency view is toggled on) underwater avatar becomes visible again and the tunnel renders fully BUT you also can see a blue ceiling corresponding to the water surface that the WES fails to hide from within. So you can see WES implementation (as seen using the latest oficial viewer) needs some improvement.

Photo Viewer

View photos in a modal