Intent to Ship: Sec-CH-Prefers-Reduced-Transparency User Preference Media Features Client Hints Header
Luke
Contact emails
lukewa...@gmail.com, lu...@warlow.devExplainer
https://github.com/wicg/user-preference-media-features-headers/blob/main/README.mdSpecification
https://wicg.github.io/user-preference-media-features-headers/#sec-ch-prefers-reduced-transparencySummary
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>CSSSearch tags
client hints, sec-ch-prefers-reduced-transparency, prefers-reduced-transparencyTAG review
TAG review status
PendingRisks
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)?
YesThe 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?
YesFlag name on chrome://flags
#enable-experimental-web-platform-featuresFinch feature name
ClientHintsPrefersReducedTransparencyRequires code in //chrome?
FalseTracking bug
https://bugs.chromium.org/p/chromium/issues/detail?id=1466423Sample links
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/6242983812268032Links 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
Mike Taylor
On 8/30/23 3:55 PM, Luke wrote:
Contact emails
lukewa...@gmail.com, lu...@warlow.dev
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
Search tags
client hints, sec-ch-prefers-reduced-transparency, prefers-reduced-transparency
TAG review
--
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+...@chromium.org.
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.
Luke
Yoav Weiss
To view this discussion on the web visit https://groups.google.com/a/chromium.org/d/msgid/blink-dev/411a7692-6ebf-483e-8700-669569e1c6a7n%40chromium.org.
Mike Taylor
LGTM2
Chris Harrelson
To view this discussion on the web visit https://groups.google.com/a/chromium.org/d/msgid/blink-dev/16d8764f-6978-490c-8a59-56aaebb34a55%40chromium.org.