Support 103 Early Hints informational responses for navigation. When a 103 response includes <link rel=preload> or other link headers Chromium tries to preload (and/or preconnect, prefetch) specified resources even before the final response is received. This gives Web developers a way to optimize Core Web Vitals such as Largest Contentful Paint (LCP).
A few months ago, we announced a collaborative experiment  to measure the potential impact of 103 early hints. The results indicate that Early Hints could result in speed improvements on the order of a few hundred milliseconds (the sample size is a bit small though). Given these encouraging results, we are now moving forward with the next steps, starting with this intent to prototype.  https://chromium.googlesource.com/chromium/src/+/master/docs/early-hints.md
Unknown standards status - check spec link for status
Status in Chromium
Consensus & Standardization
Last updated on 2021-10-17