NVidia.Nv20 = "NVIDIA GeForce3"
NVidia.Nv20.1 = "NVIDIA GeForce3 Ti 200"
NVidia.Nv20.2 = "NVIDIA GeForce3 Ti 500"
Well, i don't see the problem with that. At first, nVidia thinked they would release only ONE NV20 based GPU. Then they decided to release two more. So they didn't have the . in the original product.
Or anyway, that's my understanding - could be wrong.
NVidia.Nv25.3 = "NVIDIA NV25"
Well, there are two possibilities here...
1. This is a card nV planned in case ATI would release a 8500 refresh.
2. This was some type paradox, planned to have good memory and low clocks or something. And then they realized " Hey, we're gonna get flamed for this! "
Or maybe nVidia just wants to make people lose their time looking at it.