FYI: Due to some additional implementation work, this feature missed the M158 branch cut.
The flag flip has landed for *M159* (or whichever milestone it landed in), and ChromeStatus has been updated accordingly. 2026年10月28日(水) 14:54 Yoichi Osato <[email protected]>: > > it would be unfortunate if the major customers of this API were ad > systems. Do we have good data from non-ads use-cases? > The customer actually tested this feature on non-Ads use case:) > > 2026年10月28日(水) 3:51 Alex Russell <[email protected]>: > >> Thanks for the data. It's exciting to hear about such a large performance >> improvement. >> >> LGTM1 >> >> Not blocking, but just curious: it would be unfortunate if the major >> customers of this API were ad systems. Do we have good data from non-ads >> use-cases? >> >> Best, >> >> Alex >> >> On Wednesday, October 21, 2026 at 6:53:04 PM UTC-7 Yoichi Osato wrote: >> >>> > This Intent mentions an OT; was there feedback from developers about >>> the utility of x-origin iframe pre-rendering? >>> Yes, one of our customers shows significant performance improvement( >>> 68%!) on speculative loading with this feature. >>> >>> > Did we learn anything about the potential risks (e.g., to metrics and >>> privacy)? >>> No report from OT attendees so far. >>> >>> 2026年10月22日(木) 0:24 Alex Russell <[email protected]>: >>> >>>> Do we have a sense for which sorts of applications will benefit from >>>> this change? This Intent mentions an OT; was there feedback from developers >>>> about the utility of x-origin iframe pre-rendering? Did we learn anything >>>> about the potential risks (e.g., to metrics and privacy)? >>>> >>>> Thanks, >>>> >>>> Alex >>>> >>>> On Wednesday, October 14, 2026 at 11:28:21 PM UTC-7 Chromestatus wrote: >>>> >>>>> *Contact emails* >>>>> [email protected] >>>>> >>>>> *Explainer* >>>>> >>>>> https://github.com/WICG/nav-speculation/blob/main/prerendering-cross-origin-iframes.md >>>>> >>>>> *Specification* >>>>> https://wicg.github.io/nav-speculation/prerendering.html >>>>> >>>>> *Summary* >>>>> Prerenders cross-origin iframes with an opt-in response header. >>>>> Browsers will now prerender all cross-origin frames if the top-level >>>>> frame's HTTP response includes the Supports-Loading-Mode: >>>>> prerender-cross-origin-frames. >>>>> >>>>> *Blink component* >>>>> Blink >>>>> <https://issues.chromium.org/issues?q=customfield1222907:%22Blink%22> >>>>> >>>>> *Web Feature ID* >>>>> speculation-rules <https://webstatus.dev/features/speculation-rules> >>>>> >>>>> *Motivation* >>>>> By default, navigational prerendering delays the loading of all >>>>> cross-origin iframes until the referring page activates the prerendered >>>>> page. However, there are some cases where cross-origin iframes are >>>>> particularly important to an application, such that delaying them negates >>>>> many of the benefits of prerendering. >>>>> >>>>> *Initial public proposal* >>>>> >>>>> https://groups.google.com/a/chromium.org/g/blink-dev/c/KP1f2UTqCgM/m/q_EQ5ceXHgAJ >>>>> >>>>> *TAG review* >>>>> https://github.com/w3ctag/design-reviews/issues/1207 >>>>> >>>>> *TAG review status* >>>>> Issues addressed >>>>> >>>>> *Origin Trial Name* >>>>> Prerendering cross-origin iframes >>>>> >>>>> *Goals for experimentation* >>>>> Gather feedback from web authors who already are interested in this >>>>> feature. >>>>> >>>>> *Chromium Trial Name* >>>>> Prerender2CrossOriginIframes >>>>> >>>>> *Origin Trial documentation link* >>>>> >>>>> https://github.com/WICG/nav-speculation/blob/main/prerendering-cross-origin-iframes.md >>>>> >>>>> *WebFeature UseCounter name* >>>>> kPrerender2CrossOriginIframes >>>>> >>>>> *Risks* >>>>> >>>>> >>>>> *Interoperability and Compatibility* >>>>> The entire speculative loading feature is a progressive enhancement, >>>>> so in general risks are low in this area. >>>>> >>>>> *Gecko*: No signal ( >>>>> https://github.com/mozilla/standards-positions/issues/1376) No signal >>>>> as of 2026-10-15 >>>>> >>>>> *WebKit*: No signal ( >>>>> https://github.com/WebKit/standards-positions/issues/636) No signal >>>>> as of 2026-10-15 >>>>> >>>>> *Web developers*: Positive Our partners have given positive feedback >>>>> on this feature. >>>>> >>>>> *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. >>>>> >>>>> >>>>> *Debuggability* >>>>> The cross-origin iframe prerendering should be debuggable as well as >>>>> top frame's one: >>>>> https://developer.chrome.com/docs/devtools/application/debugging-speculation-rules#prerender >>>>> >>>>> *Will this feature be supported on all six Blink platforms (Windows, >>>>> Mac, Linux, ChromeOS, Android, and Android WebView)?* >>>>> No >>>>> >>>>> *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 about://flags* >>>>> "prerender2-cross-origin-iframes" from M148 >>>>> >>>>> *Finch feature name* >>>>> Prerender2CrossOriginIframes >>>>> >>>>> *Rollout plan* >>>>> Will ship enabled for all users >>>>> >>>>> *Requires code in //chrome?* >>>>> False >>>>> >>>>> *Tracking bug* >>>>> https://issues.chromium.org/issues/440387014 >>>>> >>>>> *Availability expectation* >>>>> Feature is available only in Chromium browsers for the foreseeable >>>>> future. >>>>> >>>>> *Adoption expectation* >>>>> Feature is used by specific partner(s) to provide functionality within >>>>> 12 months of launch in Chrome. >>>>> >>>>> *Adoption plan* >>>>> One of our partners has already joined in origin trial in Chrome and >>>>> shows better performance result. >>>>> >>>>> *Non-OSS dependencies* >>>>> >>>>> Does the feature depend on any code or APIs outside the Chromium open >>>>> source repository and its open-source dependencies to function? >>>>> No. >>>>> >>>>> *Estimated milestones* >>>>> Shipping on desktop 158 >>>>> Origin trial desktop first 147 >>>>> Origin trial desktop last 152 >>>>> Origin trial extension 1 end milestone 158 >>>>> Shipping on Android 158 >>>>> Shipping on WebView 158 >>>>> Shipping on iOS 158 >>>>> >>>>> *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/5112398709129216?gate=5121426126405632 >>>>> >>>>> *Links to previous Intent discussions* >>>>> Intent to Prototype: >>>>> https://groups.google.com/a/chromium.org/d/msgid/blink-dev/68b670ba.050a0220.270bc4.0593.GAE%40google.com >>>>> Intent to Experiment: >>>>> https://groups.google.com/a/chromium.org/d/msgid/blink-dev/CAAEV3p%3DzhNhfOpe8x%3DRKgxYFS9GCq_q-c8knZYRBRuijQ27o8w%40mail.gmail.com >>>>> Intent to Extend Experiment 1: >>>>> https://groups.google.com/a/chromium.org/d/msgid/blink-dev/6a45fcf5.198129d7.1d0cd0.0014.GAE%40google.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. 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