Contact emails aric...@chromium.org, jadekess...@chromium.org, miketa...@chromium.org
Design Doc https://docs.google.com/document/d/1U3P9yvaT1NXG_qRmY3Lp6Me7M5kTnd3QrBb1yFUVNNk/edit Specification https://wicg.github.io/client-hints-infrastructure/ Intent to Prototype https://groups.google.com/a/chromium.org/g/blink-dev/c/FTNrw03Xs9s/m/O74Mp6bmCAAJ Summary To support content negotiation use cases such as differential serving of variable fonts <https://developer.mozilla.org/en-US/docs/Web/CSS/CSS_Fonts/Variable_Fonts_Guide>, color vector fonts <https://www.chromestatus.com/feature/5638148514119680>, responsive images <https://github.com/w3c/webappsec-permissions-policy/issues/55#issuecomment-406627096>, and other third-party content which requires client information lost by user agent reduction <https://groups.google.com/a/chromium.org/g/blink-dev/c/R0xKm1B7qoQ>. For example: variable fonts <https://developer.mozilla.org/en-US/docs/Web/CSS/CSS_Fonts/Variable_Fonts_Guide> allow significantly less font information to be transferred without loss of functionality, but only works on specific operating systems. Blink component Blink>Network>ClientHints <https://bugs.chromium.org/p/chromium/issues/list?q=component%3ABlink%3ENetwork%3EClientHints> Motivation It’s already possible to set a Permissions Policy <https://wicg.github.io/ua-client-hints/#delegation> in the HTTP response header, but for sites without the ability to modify HTTP headers a HTML solution would be ideal. This proposal ships a meta tag which allows delegation of client hints to third-party origins. These tags could be included in code-snippets for embedded third-party content for ease of use. For example, to specify third party requests to `https://foo.bar` must include `sec-ch-width` you could include: <meta name="accept-ch" content="sec-ch-width=( https://foo.bar )"> You may still omit the permission policy and rely on the default allowlist as follows: <meta name="accept-ch" content="sec-ch-width"> Note that this is the equivalent of the following today: <meta http-equiv="accept-ch" content="sec-ch-width"> TAG review https://github.com/w3ctag/design-reviews/issues/702 Compatibility We do not anticipate compatibility risks for this addition - Blink currently implements first party client hints via a `http-equiv` meta tag, and that functionality will not be removed or modified. Interoperability Gecko: Neutral <https://github.com/mozilla/standards-positions/issues/596> WebKit: Requested <https://lists.webkit.org/pipermail/webkit-dev/2021-November/032057.html> Web developers: Positive interest from Cloudinary <https://bugs.chromium.org/p/chromium/issues/detail?id=1219359#c10> Debuggability Any improperly formatted client hint meta tags will be flagged in the Issues tab <https://docs.google.com/document/d/1lDEvj8tMeuvUs1HTTqL-44YiI-7ljeQkusM_WhUfIeE/edit> . Is this feature fully tested by web-platform-tests? https://github.com/web-platform-tests/wpt/pull/32142 Tracking bug https://crbug.com/1219359 Link to entry on the Chrome Platform Status https://www.chromestatus.com/feature/5684289032159232 -- You received this message because you are subscribed to the Google Groups "blink-dev" group. To unsubscribe from this group and stop receiving emails from it, send an email to blink-dev+unsubscr...@chromium.org. To view this discussion on the web visit https://groups.google.com/a/chromium.org/d/msgid/blink-dev/CAGpy5D%2BCMCakKz0dH9C-d7%3D75446vu-j3geD5ZgbKmQSsQm9vA%40mail.gmail.com.
