javascript.builtins.Temporal - Safari `impl_url` references outdated WebKit umbrella bug

What type of issue is this?

Other

What information was incorrect, unhelpful, or incomplete?

The Safari compatibility data for Temporal currently reports Safari Technology Preview support, which appears to be correct, but many of the individual Temporal entries still use the original WebKit umbrella bug as their impl_url:

https://bugs.webkit.org/show_bug.cgi?id=223166

For example, javascript/builtins/Temporal/Instant.json currently contains:

"safari": {
  "version_added": "preview",
  "impl_url": "https://webkit.org/b/223166"
}

Bug 223166 is still open as an umbrella tracker, so I do not believe the link is strictly invalid. However, it no longer gives a clear picture of the current implementation status.

In particular, significant implementation work has since landed under newer WebKit bugs and pull requests, including the full Temporal.ZonedDateTime implementation and the change that enabled the Temporal global by default.

This can make the current impl_url misleading when following BCD/MDN's compatibility data to determine the current state of Safari's Temporal implementation.

What browsers does this problem apply to, if applicable?

Safari

What did you expect to see?

I expected the Safari impl_url metadata to reference the more recent WebKit implementation or enablement work, where appropriate, or for the older umbrella link to be removed if there is no single implementation issue that accurately represents the current state.

In particular, WebKit bug 318885 seems relevant to the top-level Safari support entry because it tracks the change that actually enabled the Temporal object by default.

I am not suggesting that the current:

"version_added": "preview"

value should be changed. I have not found sufficient evidence that a stable Safari release exposes Temporal yet.

The issue is specifically with the usefulness/currentness of the implementation-tracking URL.

Did you test this? If so, how?

I did not test Safari Technology Preview directly because I do not currently have access to a Mac.

Instead, I verified the compatibility data and traced the corresponding upstream WebKit history:

1. Inspected the current BCD Temporal data and confirmed that multiple Safari entries use WebKit bug 223166 as their impl_url.
2. Verified that WebKit PR #66111 landed the full Temporal.ZonedDateTime implementation on June 4, 2026.
3. Verified that WebKit PR #68930 changed JavaScriptCore's useTemporal option from false to true and landed on July 8, 2026.
4. Verified that Safari Technology Preview 249 subsequently announced support for the Temporal object.

These sources appear consistent with BCD's current "version_added": "preview" value while suggesting that bug 223166 is no longer the most useful implementation-status reference.

Can you link to any release notes, bugs, pull requests, or MDN pages related to this?

Original WebKit Temporal umbrella bug:

• https://bugs.webkit.org/show_bug.cgi?id=223166

Full Temporal.ZonedDateTime implementation:

• https://bugs.webkit.org/show_bug.cgi?id=315939
• https://github.com/WebKit/WebKit/pull/66111

Enable Temporal by default:

• https://bugs.webkit.org/show_bug.cgi?id=318885
• https://github.com/WebKit/WebKit/pull/68930

Safari Technology Preview 249 release notes, which state “Added support for the Temporal object”:

• https://webkit.org/blog/18182/release-notes-for-safari-technology-preview-249/

Current BCD Temporal data:

• https://github.com/mdn/browser-compat-data/tree/main/javascript/builtins/Temporal

Do you have anything more you want to share?

The original WebKit bug still appears useful as an umbrella issue for remaining Temporal correctness and conformance work, so replacing it everywhere with one newer bug may not necessarily be the right solution.

I primarily wanted to flag the metadata because following the current impl_url can give the impression that Safari's Temporal implementation is still waiting on older or superseded implementation work, despite WebKit having since enabled Temporal by default and shipped it in Safari Technology Preview.

I would defer to the BCD maintainers on whether the best solution is to update individual impl_url values, use the newer enablement bug for the top-level feature, retain the umbrella issue only where appropriate, or remove some of the links.

MDN URL

https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Temporal

MDN metadata

MDN page report details

• Query: javascript.builtins.Temporal
• Report started: 2026-08-26T21:39:46.878Z

Inspect the entries under javascript/builtins/Temporal, including Temporal/Instant.json, and compare their Safari impl_url values with the linked WebKit bugs and pull requests. Determine which entries should reference newer implementation or enablement work, while preserving version_added: preview, then validate the updated compatibility data.