Re: [csswg-drafts] Update text/css registration (#5310)

> Currently the text/css registration is that in [RFC2318](https://tools.ietf.org/html/rfc2318), which refers to CSS1, and its definition of the `charset` parameter seems completely bogus (and doesn't fulfil [RFC6657](https://tools.ietf.org/html/rfc6657)'s recommendations).

RFC 6657 has a[SHOULD](https://datatracker.ietf.org/doc/html/rfc6657#section-3) which says

a.  specify that the "charset" parameter is not used for the defined
       subtype, because the charset information is transported inside
       the payload (such as in "text/xml"), or

   b.  require explicit unconditional inclusion of the "charset"
       parameter, eliminating the need for a default value.

For CSS, to be web compatible, we can't _disallow_ `charset` (we do have `@charset for internal labelling, but it is not mandatory and rarely used). We also can't _require_ `charset` because it is rarely used. And we can't declare a default charset because [the actual algorithm is more complicated](https://drafts.csswg.org/css-syntax/#determine-the-fallback-encoding)

So (as this is SHOULD not MUST, and Web Compat is a good reason) I believe this section should just link to CSS Syntax 3, TR version, [determine the fallback encoding of a stylesheet](https://www.w3.org/TR/css-syntax-3/#determine-the-fallback-encoding) 


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Received on Thursday, 15 January 2026 21:46:52 UTC