Not really, since the shape of the blackbody emissions curve converges (when restricted to the visible wavelength range and normalized). 10^5 K should be very close to infinity.

“Not really” to which part?

That it's not an extrapolation. The physics part converges and stops varying.

The article actually points out to the fact that colour is not dependent on the Planck’s Law: “So, for an extremely hot blackbody, the spectrum of light we can actually see with our eyes is governed by the Rayleigh–Jeans law. This law says the color doesn’t depend on the temperature: only the brightness does!”

But then the Rayleigh-Jeans Law has been shown to be incorrect, see Ultraviolet Catastrophe.

Well yes but no: it's still the correct infrared limit (or high-temperature limit) of Planck's law, in fact Wikipedia has the derivation from one to the other:

https://en.wikipedia.org/wiki/Rayleigh%E2%80%93Jeans_law#Com...

The colour computed in the article is anything but infrared, it is at the other end of the planckian locus.

When physicists say something is true in the infrared limit, they mean that it is true for low enough wavelengths. In this case the exact definition of "low enough" depends on the temperature. If the temperature is high enough, then that set of "low enough" wavelengths will include the entire visible part of the spectrum. So as T goes to infinity, the light that we can actually see will get brighter and brighter, but the relative power emitted at different wavelengths will stay the same, so the colour will stay the same. But that's just in the visible region. There will be higher and higher frequency x rays and gamma rays emitted, eventually to the point of being lethal to a human observer.

That's why they said infrared or high-temperature.

Combined it's: Anywhere the temperature is high relative to the frequencies being analyzed.