[css-mediaqueries-4] Unused mf-eq token in level 4

[stephen]

In the syntax section, <mf-comparison> includes a rule for <mf-eq>. I think that would imply that syntaxes like:

@media (min-width = 600px);

are valid.

However, I didn't see any other informal mentions of ='s syntax in the spec, or why it'd be interpreted differently from the existing: syntax (e.g. @media (min-width: 600px);).

I see that this change was made in d8e702d without (I think) intending to introduce this syntax, as <= and >= are covered by <mf-lt> and <md-gt> productions.

Is this an error in the spec, or is there something I'm missing?