In recent news, Google has put forth a proposal known as the "Web Environment Integrity Explainer", authored by four of its engineers. On the surface, it
Nothing. They've already made commits to the Chromium repository adding in experimental support. It'll be up to vendors to patch it out or disable it if they want to. I sincerely doubt Microsoft will bother if they aren't already fully on-board with the proposal and just itching for the feature to finalize and release upstream.