It's a muddy comparison given that NumPy is commonly used with other BLAS implementations, which the author even lists, but doesn't properly address. Anaconda defaults to Intel oneAPI MKL, for example, and that's a widely used distribution. Not that I think MKL would do great on AMD hardware, BLIS is probably a better alternative.
The author also says "(...) implementation follows the BLIS design", but then proceeds to compare *only* with OpenBLAS. I'd love to see a more thorough analysis, and using C directly would make it easier to compare multiple BLAS libs.
"Linux x86_64" is present on my UA on Linux, and "Windows NT 10.0; Win64; x64" on Windows. Probably a bug or just untested on Firefox. Just a bit annoying.
I'll add that this is the first site that misdetects anything like that.