http.headers.Link.blocking - Unclear where this is specified?

[gsnedders]

What type of issue is this?

Other

What information was incorrect, unhelpful, or incomplete?

We currently have:

browser-compat-data/http/headers/Link.json

Line 40 in f9db401

"spec_url": "https://html.spec.whatwg.org/multipage/semantics.html#attr-link-blocking",

This defines the blocking attribute on the HTML link element, which we have data in BCD for in:

browser-compat-data/html/elements/link.json

Line 86 in f9db401

"blocking": {

What browsers does this problem apply to, if applicable?

No response

What did you expect to see?

A link to some spec defining the blocking target attribute for the Link header.

Did you test this? If so, how?

N/A

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

Neither https://html.spec.whatwg.org/multipage/semantics.html#process-link-headers nor https://html.spec.whatwg.org/multipage/semantics.html#apply-link-options-from-parsed-header-attributes seem to read the "blocking" target attribute, so I don't see where this is specified?

Do you have anything more you want to share?

No response

MDN URL

https://developer.mozilla.org/en-US/docs/Web/HTTP/Reference/Headers/Link

MDN metadata

MDN page report details

• Query: http.headers.Link
• Report started: 2025-05-22T22:03:24.733Z

[gsnedders]

I think this might've been removed in whatwg/html#7935?

This would imply this also shouldn't be part of the 'blocking="render"' web feature, which Safari shows as unavailable because http.headers.Link.blocking is unsupported.

[caugner]

The data was added in October 2024 as part of adding fetchpriority.

However, the Processing Link headers section only includes fetchpriority, not blocking. When fetchpriority was added in whatwg/html#8470, blocking was already not in that list.

So I think we should remove http.headers.Link.blocking from BCD. @gsnedders Do you agree?

PS: whatwg/html#8742 made it a bit clearer which link types have Link processing.