Open-Source GPU Kernel Modules does not support GM206 [GeForce GTX 960] [10de:1401] (rev a1)

Open-Source GPU Kernel Modules does not support GM206 [GeForce GTX 960]
although listed here:
Supported Products

NVRM: The NVIDIA GPU 0000:01:00.0 (PCI ID: 10de:1401)
NVRM: installed in this system is not supported by the
NVRM: NVIDIA 515.43.04 driver release.                                         

lspci -nn
01:00.0 VGA compatible controller [0300]: NVIDIA Corporation GM206 [GeForce GTX 960] [10de:1401] (rev a1)

That is the binary driver you linked to. You need a Turing GPU.

Which GPUs are supported by open GPU kernel modules?
Open kernel modules support all NVIDIA Ampere and Turing architecture GPUs. Datacenter GPUs are supported for production, and support for GeForce and Workstation GPUs is alpha quality. For more information, see the Datacenter, NVIDIA RTX, and GeForce CUDA GPUs product tables (NVIDIA Turing and later GPUs have compute capability of 7.5 or greater).

https://developer.nvidia.com/blog/nvidia-releases-open-source-gpu-kernel-modules/

Thanks for your answers so far.
Most valuable information regarding my issue, I found here:
Clarification on GPU support for Maxwell/Pascal archs and binary/OS relationship #19