CSS has added a new display-p3-linear color space: https://drafts.csswg.org/css-color/#predefined-display-p3-linear

Both Chromium and Firefox have announced the intent to ship the new color space.

I don't know whether Safari is already shipping it or no, but it will probably ship it anyway given that this new colorspace was proposed by Apple according to w3c/csswg-drafts#12596