Chrome’s Site Isolation is an essential security defense that makes it harder for malicious web sites to steal data from other web sites. Starting in Chrome 92, it will apply to sites where users log in via third-party providers, as well as sites that carry Cross-Origin-Opener-Policy headers. Chrome will also disable V8 runtime mitigations for Spectre on Android, which are less effective and impose a performance cost. We advise that sites wanting to protect data from Spectre should consider serving COOP headers.”]
Source: https://security.googleblog.com/2021/07/protecting-more-with-site-isolation.html