Subject: Re: [Technical Errata Reported] RFC9110 (9162)
From: Sean McArthur <[email-masked]>
To: Nico Williams <[email-masked]>
Cc: Julian Reschke <[email-masked]>, [email-masked]
Date: Thu, 3 Sep 2026 10:30:54 -0400
List-Id: <ietf-http-wg.w3.org>

Unfortunately, some header implementations decided OWS is not actually
allowed. The `Access-Control-Request-Headers` is one of them, and they even
have a note about it "for better or worse".
https://fetch.spec.whatwg.org/#cors-preflight-fetch

On Thu, Sep 3, 2026 at 10:24 AM Nico Williams <[email-masked]> wrote:

> On Thu, Sep 03, 2026 at 12:29:06PM +0200, Julian Reschke wrote:
> > Am 03.09.2026 um 11:31 schrieb Rory Hewitt:
> > > I would prefer the definition to say "...separated by a comma, with
> > > optional white space (OWS)" - does optional mean it shouldn't be
> > > mentioned?
> >
> > That would make the behavior non-deterministic.
>
> Isn't it already so?
>
>