LGTM1; thanks for the note about interop risk, makes this easier to approve.
On Monday, October 26, 2026 at 2:56:32 PM UTC-7 Chromestatus wrote: > *Contact emails* > [email protected] > > *Specification* > https://drafts.csswg.org/css-values-4/#linked-properties > > *Summary* > Makes the computed value of the background-* longhands keep the number of > comma-separated values the author specified, instead of repeating or > truncating it to the background-image layer count. Repeating and truncating > are used-value behavior: "The computed values of the coordinating list > properties are not affected by such truncation or repetition." This feature > would implement the behavior defined in the > https://drafts.csswg.org/css-values-4/ Appendix A. > > *Blink component* > Blink>CSS > <https://issues.chromium.org/issues?q=customfield1222907:%22Blink%3ECSS%22> > > *Web Feature ID* > background <https://webstatus.dev/features/background> > > *Motivation* > The behavior defined in the "Appendix A: Coordinating List-Valued > Properties" of the CSS Values And Units L4 specification has been discussed > recently and agreed that it should stand. This makes Chrome the only > browser diverging in the specified behavior. > > *Initial public proposal* > *No information provided* > > *TAG review* > *No information provided* > > *TAG review status* > Not applicable > > *Goals for experimentation* > None > > *Risks* > > > *Interoperability and Compatibility* > The new behavior this feature provides is implemented already by Firefox > and Safari, so it's Chrome catching up in this case; hence, the interop > risk is zero. Regarding compatibility, making the background-* properties > align "coordinated list group" is what matches the current specified > behavior, which the CSSWG agreed on keep. Some engines implemented weird > truncation rules, that's why there were some WPT not following the spec. > The resolution [1] was to update the tests and observe whether any compat > issue appears in the next months. [1] > https://github.com/w3c/csswg-drafts/issues/12791#issuecomment-4040285092 > > *Gecko*: Shipped/Shipping Firefox was the only one implementing the > behavior defined in the spec. > https://github.com/w3c/csswg-drafts/issues/12791#issuecomment-4040285092 > > *WebKit*: Shipped/Shipping ( > https://developer.apple.com/documentation/safari-technology-preview-release-notes/stp-release-246) > See > the bug https://bugs.webkit.org/show_bug.cgi?id=315771 for details > > *Web developers*: No signals > > *Other signals*: > > *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? > *No information provided* > > > *Debuggability* > *No information provided* > > *Will this feature be supported on all six Blink platforms (Windows, Mac, > Linux, ChromeOS, Android, and Android WebView)?* > Yes > > *Is this feature fully tested by web-platform-tests > <https://chromium.googlesource.com/chromium/src/+/main/docs/testing/web_platform_tests.md>?* > Yes > * > https://wpt.fyi/results/css/css-backgrounds/parsing?label=experimental&label=master&aligned > > * > https://wpt.fyi/results/css/css-backgrounds/animations/background-position-interpolation.html?label=experimental&label=master&aligned > > * > https://wpt.fyi/results/css/css-backgrounds/animations/background-size-interpolation.html?label=experimental&label=master&aligned > > * > https://wpt.fyi/results/css/css-masking/parsing?label=experimental&label=master&aligned > > *Flag name on about://flags* > *No information provided* > > *Finch feature name* > *No information provided* > > *Non-finch justification* > *No information provided* > > *Rollout plan* > Will ship enabled for all users > > *Requires code in //chrome?* > False > > *Tracking bug* > https://issues.chromium.org/issues/40855581 > > *Estimated milestones* > Shipping on desktop 159 > Shipping on Android 159 > Shipping on WebView 159 > Shipping on iOS 159 > > *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). > *No information provided* > > *Link to entry on the Chrome Platform Status* > https://chromestatus.com/feature/5144333908049920?gate=6114123363516416 > > *Links to previous Intent discussions* > Intent to Prototype: > https://groups.google.com/a/chromium.org/g/blink-dev/c/eny3Exk0b8w/m/HiXscXadAgAJ > > > 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 visit https://groups.google.com/a/chromium.org/d/msgid/blink-dev/1a9a7278-d5a2-42a7-8556-2086d23e5fa9n%40chromium.org.
