blend4web – What output file do I need for this effect on Sketchfab?

what output files I need for this viewing experience.

Export as obj or fbx, the usual. It’s nothing more than a mesh after all.
Your Mesh(es) (.obj, fbx, etc.) + eventual libraries (.mtl,etc.), your textures (2 in this case) and that’s all. Drag and drop those files in Sketchfab’s upload webpage. And it will do the rest.

I understand how to make the effect, but I have no idea what output files […]

You understand how it’s made? Then make it. I don’t really see what’s your issue here.