api.CustomElementRegistry - Scoped custom element registry, Safari TP 214 supports constructor

What type of issue is this?

Missing compatibility data

What information was incorrect, unhelpful, or incomplete?

The CustomElementRegristry data will need to be changed to account for the new "Scoped custom element registry" feature, which lets developers create their own registries, in addition to using the global one (via window.customElements).

My understanding is that you can now do new CustomElementRegistry(). This wasn't possible before.

What browsers does this problem apply to, if applicable?

No response

What did you expect to see?

New BCD data that captures the fact that new CustomElementRegistry() works in some browsers.

Did you test this? If so, how?

I tested the above JS expression in Chromium, and it worked there. I am unclear as to whether the feature is implemented fully/correctly in Chromium, because the Chromestatus entry isn't showing the feature has having shipped, and was last updated in 2022: https://chromestatus.com/feature/5090435261792256

This comment: https://github.com/whatwg/html/issues/10854#issuecomment-2816888199 says that the feature has shipped in Safari TP.
See STP214 release notes: https://developer.apple.com/documentation/safari-technology-preview-release-notes/stp-release-214#Web-API

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

MDN page related to this: https://developer.mozilla.org/en-US/docs/Web/API/CustomElementRegistry

HTML spec, which now mentions the feature: https://html.spec.whatwg.org/multipage/custom-elements.html#custom-elements-api

Do you have anything more you want to share?

Corresponding MDN content issue: https://github.com/mdn/content/issues/38266

MDN URL

https://developer.mozilla.org/en-US/docs/Web/API/CustomElementRegistry

Start with the api.CustomElementRegistry entry and review the HTML spec, Safari Technology Preview 214 release notes, MDN's CustomElementRegistry page, and the linked Chromium and WHATWG discussions. Verify which browsers support new CustomElementRegistry(), then update the compatibility data with confirmed support and ensure the entry distinguishes this scoped-registry feature.