What's the difference between gaussians.spz and vrGaussians.spz?

They are associated to each scan, they are listed in each scan page, inside tag “script#NEXT_DATA”; my page extracts and shows the links to them:

But apparently the files differ by just 10% in size.

Is the lack of vrGaussians.spz file to trigger the “scan not optimized for VR” error message in Quest viewer?