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Explainer https://github.com/wicg/user-preference-media-features-headers/blob/main/README.md Specification https://wicg.github.io/user-preference-media-features-headers/#sec-ch-prefers-reduced-transparency Summary User Preference Media Features Client Hints Header defines a set of HTTP Client Hints headers around user preference media features as defined by Media Queries Level 5. If used as Critical Client Hints, these headers allow servers to make smart choices regarding, e.g., CSS inlining. Sec-CH-Prefers-Reduced-Transparency reflects the user's prefers-reduced-transparency preference. Blink component Blink>CSS <https://bugs.chromium.org/p/chromium/issues/list?q=component:Blink%3ECSS> Search tags client hints <https://chromestatus.com/features#tags:client%20hints>, sec-ch-prefers-reduced-transparency <https://chromestatus.com/features#tags:sec-ch-prefers-reduced-transparency>, prefers-reduced-transparency <https://chromestatus.com/features#tags:prefers-reduced-transparency> TAG review TAG review status Pending Risks Interoperability and Compatibility Gecko: No signal (https://github.com/mozilla/standards-positions/issues/526) WebKit: No signal (https://github.com/WebKit/standards-positions/issues/15) Web developers: Positive (WICG proposal Issue: https://github.com/WICG/proposals/issues/30 with feedback from developers working for Facebook and Magento. Twitter: https://twitter.com/kilianvalkhof/status/1392404416335056896. The proposal was initially discussed in https://github.com/w3c/csswg-drafts/issues/4162 and received positive feedback via 18 Likes) Other signals: Activation Developers will include Sec-CH-Prefers-Reduced-Transparency in the response headers Accept-CH and Critical-CH to let the browser know that they’re interested in the user's transparency preferences. If supported, the request header Sec-CH-Prefers-Reduced-Transparency will be populated with the appropriate value. This follows the same pattern as existing Preference Client Hints and as such should be easy for developers to make use of. Security This feature could be used for fingerprinting as it exposes a user preference. However, this is already exposed to CSS/JS by the `prefers-reduced-transparency` media query. WebView application risks Does this intent deprecate or change behavior of existing APIs, such that it has potentially high risk for Android WebView-based applications? Debuggability Developers can change this client hint header value by emulating prefers-reduced-transparency via Devtools in the Rendering Panel. Will this feature be supported on all six Blink platforms (Windows, Mac, Linux, Chrome OS, Android, and Android WebView)? Yes The feature will be supported on all platforms, but whether the user will be able to signal a reduced transparency preference depends on the OS. Is this feature fully tested by web-platform-tests <https://chromium.googlesource.com/chromium/src/+/main/docs/testing/web_platform_tests.md>? Yes Flag name on chrome://flags #enable-experimental-web-platform-features Finch feature name ClientHintsPrefersReducedTransparency Requires code in //chrome? False Tracking bug https://bugs.chromium.org/p/chromium/issues/detail?id=1466423 Sample links https://sec-ch-prefers-reduced-transparency.glitch.me <https://sec-ch-prefers-reduced-transparency.glitch.me/> Estimated milestones Shipping on desktop 118 DevTrial on desktop 118 Shipping on Android 118 DevTrial on Android 118 Anticipated spec changes Open questions about a feature may be a source of future web compat or interop issues. Please list open issues (e.g. links to known github issues in the project for the feature specification) whose resolution may introduce web compat/interop risk (e.g., changing to naming or structure of the API in a non-backward-compatible way). Link to entry on the Chrome Platform Status https://chromestatus.com/feature/6242983812268032 Links to previous Intent discussions Intent to prototype: https://groups.google.com/a/chromium.org/d/msgid/blink-dev/B1ED49A6-31BF-4D28-89B3-D2973F9F12DA%40gmail.com This intent message was generated by Chrome Platform Status <https://chromestatus.com/>. -- 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/6B4E754E-49E5-47DE-B473-4AC40FC0C599%40gmail.com.
