To nitpick the other answers its actually called Image-Based Lighting (IBL), which is a fancier PBR technique compared to traditional environment-mapping
You can tell it's not raytracing because you can't see the ear of the head reflected into the head. That's the tell-tale sign of raytracing, when an object reflects into itself.
No, it's environment mapping.
All I can see is a cube map. Looking at the source code of the scene confirms this: it's just a traditional skybox projected onto the mesh.
No raytracing there, just plain old cube-mapped reflections.
Without looking at the code, I doubt it. Real-time reflections are generally done with offscreen rendering and cube maps. The objects being reflected are still rendered, you just can't see them because they aren't in the projection/view space.
The scene being reflected is almost certainly pre-rendered. Fun fact: it's the Cornell Box, a very common placeholder scene in computer graphics.