Hi Webkit-Dev,

We're preparing to ship an extension to the HTTP Link header to allow a source site to tell the browser that subresources of a page it's prenavigating to, may be retrieved as signed exchanges from the source site. We're aware that you currently oppose the existence of signed exchanges, but we'd still appreciate your thoughts on the new use of `Link: …; rel=alternate; anchor=...`.

 - Explainer:
   https://github.com/WICG/webpackage/blob/master/explainers/signed-exchange-subresource-subtitution-explainer.md

And also we'd welcome any updates on WebKit’s position about Signed HTTP Exchanges.

Signed HTTP Exchanges
 - Explainer:
   https://developers.google.com/web/updates/2018/11/signed-exchanges
 - Specification:
   Signed Exchanges format:
     https://wicg.github.io/webpackage/draft-yasskin-http-origin-signed-responses.html
   Loading signed exchanges:
     https://wicg.github.io/webpackage/loading.html
 - ChromeStatus: https://chromestatus.com/feature/5745285984681984

Signed HTTP Exchange was launched in Chrome 73 (released in March 2019).
We are planning on shipping this extension to the HTTP link header. We believe that this extension makes Signed HTTP Exchanges more useful, i.e. applicable beyond  the AMP specific use-case we’ve had so far.
https://groups.google.com/a/chromium.org/forum/#!msg/blink-dev/tybtqf-tdB4/L77qLrHJAQAJ


Thank you.