• Specification (Add display-p3-linear as a supported color space #4167)
• Dart Sass (Add support for the display-p3-linear color space dart-sass#2703)
• Embedded Node.js Host (Add support for the display-p3-linear color space embedded-host-node#405)
• Tests (Add tests for the display-p3-linear color space sass-spec#2095)
• Documentation (Document support for display-p3-linear sass-site#1509)

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