Unfortunately, this uses a horribly inaccurate algorithm that's been floating around the internet for more than a decade [1]. It seems that the Firefox dev tools do the same thing [2]. As far as I'm concerned, this is worse than not having such a simulation at all, since it gives people a false sense of accommodating individuals with color vision deficiencies.

The Colorspacious Python library [3] does a proper job, using the algorithm of Machado et al. (2009) [4], which is what's considered state-of-the-art.

[1] https://github.com/MaPePeR/jsColorblindSimulator#the-colorma... [2] https://hg.mozilla.org/mozilla-central/annotate/tip/devtools... [3] https://colorspacious.readthedocs.io/en/latest/tutorial.html... [4] https://doi.org/10.1109/TVCG.2009.113