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Design Doc https://docs.google.com/document/d/1sRYGWL2H_qFQamffUbojBiQdbJ1uAmptr3F_jjx5VSI/edit Specification https://wicg.github.io/savedata/ https://wicg.github.io/client-hints-infrastructure/ Summary The Sec-CH-Save-Data client hint <https://wicg.github.io/client-hints-infrastructure/> indicates whether the user agent intends to reduce data usage. It will be sent by default on all requests unless the permissions policy says otherwise. For example, one could limit delegation of this hint via HTTP headers: Permissions-Policy: ch-save-data=(self, https://bar.com/) Or, one could limit delegation of this hint via an HTML meta tag: <meta name="Accept-CH" content="sec-ch-save-data=(https://bar.com/)"> Example of new HTTP header when Data Saver is on: Sec-CH-Save-Data: ?1 Example of new HTTP header when Data Saver is off: Sec-CH-Save-Data: ?0 Explicitly requesting Sec-CH-Save-Data or modifying the CH-Save-Data permissions policy will prevent the old `Save-Data` header from being sent. Otherwise, the old header will not be affected. Blink component Blink>Network>ClientHints <https://bugs.chromium.org/p/chromium/issues/list?q=component%3ABlink%3ENetwork%3EClientHints> Motivation The current `Save-Data` header is sent when a browser or operating system data saver setting is on (e.g., Lite mode <https://support.google.com/chrome/answer/2392284?hl=en&co=GENIE.Platform%3DAndroid>) for all first and third party requests, lives outside the client hints system <https://wicg.github.io/client-hints-infrastructure/>, and is named improperly <https://docs.google.com/document/u/1/d/1yhVLyEIpDhhDQf698WkvXBiPcLwxEgCBI4o1FjvXwfM/edit>. `Sec-CH-Save-Data` will be a proper client hint and its delegation to third parties could be prevented via permissions policies <https://wicg.github.io/client-hints-infrastructure/#policy-controlled-features> . TAG review N/A (No new data is exposed that wasn't before) Compatibility The `Save-Data` header will not be removed, so adoption of `Sec-CH-Save-Data` is optional. Interoperability Gecko: Client Hints not yet implemented (considered non-harmful <https://mozilla.github.io/standards-positions/#http-client-hints>) WebKit: Client Hints not yet implemented Web developers: No feedback yet Debuggability N/A Is this feature fully tested by web-platform-tests? Not yet, but it will be. `Save-Data` tests are here <https://github.com/web-platform-tests/wpt/search?q=save-data>. Tracking bug https://crbug.com/1293443 Link to entry on the Chrome Platform Status https://chromestatus.com/feature/5645928215085056 -- 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 [email protected]. To view this discussion on the web visit https://groups.google.com/a/chromium.org/d/msgid/blink-dev/CAGpy5D%2BVOJi0s_QDuOeL%3DGNDAP1-w%3DuWqKGSLESnwXGKGqo1uQ%40mail.gmail.com.
