Subject: draft-ietf-httpbis-expect-ct-04, "2.3.2. HTTP-Equiv <meta> Element Attribute"

From: Julian Reschke <[email-masked]>
Date: Mon, 21 May 2018 09:16:31 +0200

"UAs MUST NOT heed http-equiv="Expect-CT" attribute settings on <meta> 
elements [HTML] [HTML5] in received content."

Here be dragons.

1. HTML and HTML5 appear in a "MUST NOT" statement, yet are listed as 
informative references.

2. Even if they were normative references, we'd have to tell readers 
which one takes precedence (surprise: the description of http-equiv is 
indeed different in these two - see 
<https://www.w3.org/Bugs/Public/show_bug.cgi?id=18025>).

3. AFAIU, this spec *can't* make normative requirements on HTML 
consumers. That's what the HTML spec is for.

4. Finally, the HTML spec already says that "Expect-CT" is 
non-conforming and to be ignored.

Given these points, I believe the simplest possible fix is to drop this 
section.

Best regards, Julian

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From: Emily Stark <[email-masked]>
Date: Mon, 21 May 2018 10:07:55 -0700

> non-conforming and to be ignored.

Where is that? I don't see any mention of Expect-CT in either HTML.

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From: Mark Nottingham <[email-masked]>
Date: Tue, 22 May 2018 09:44:24 +1000

I don't see anywhere that it says precisely that, but it does say http-equiv is an enumerated attribute:
  https://html.spec.whatwg.org/#attr-meta-http-equiv

That said, I agree that we shouldn't be putting requirements onto HTML. I think you could do something like this:

UAs should note that since "Expect-CT" is not an enumerated attribute of http-equiv on <meta> elements [HTML][HTML5], they are to be ignored.

Cheers,

> On 22 May 2018, at 3:07 am, Emily Stark <[email-masked]> wrote:
> 
> 
> 
> On Mon, May 21, 2018 at 12:27 AM Julian Reschke <[email-masked]> wrote:

--
Mark Nottingham   https://www.mnot.net/

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From: Julian Reschke <[email-masked]>
Date: Tue, 22 May 2018 05:50:21 +0200

On 2018-05-21 19:07, Emily Stark wrote:
> 
> 
> On Mon, May 21, 2018 at 12:27 AM Julian Reschke <[email-masked] 
> <mailto:[email-masked]>> wrote:
> 
> ...

It defines (a) which values are conforming and (b) what have an effect.

This can be changed, but it would be a change to the HTML spec.

Best regards, Julian