[css-conditional-5] Remove definitions of <font-format> and <font-tech>

[cdoublev]

Would it be possible to remove the definitions of <font-format> and <font-tech> from CSS Conditional 5?

The spec says:

This level of the specification extends the <supports-feature> syntax

But it does not extend these subproductions. Worse: <font-format> is only a subset of what is defined in CSS Fonts.

These duplicate definitions must be specifically handled in w3c/webref, by defining an "authoritative source" for the production, which is not great.

[drott]

Worse: is only a subset of what is defined in CSS Fonts.

Are you referring to the <string> production? This is the legacy part of format() which is intentionally not included in the conditionals definition.

Regarding the PR: What does the spec look like after bikeshed processing - do the font-tech and font-format become clickable references to fonts-4? font-format would then no longer be correctly defined.

[cdoublev]

Are you referring to the <string> production?

Yes. Should it be invalid in @supports but valid in src for @font-face?

If so, I will close my PR but I think it should be defined in prose (more simple) or in the syntax. I think rewriting the syntax would require to not define font-tech() as a type (<font-tech()> = ...) but as a context-sensitive function (font-tech() = ...).

I did not check the result in Bikeshed, which reports an error for duplicate type refs of <font-tech> in CSS Conditional 5 and CSS Fonts 5, and generates a link to CSS Fonts 5 for <font-format>. I do not know well how it works in details and I do not really understand why it generates a link to CSS Fonts 5 for <font-format> but not <font-tech>.

[cdoublev]

I updated the PR to import <font-format> and <font-tech> from CSS Fonts by defining that "a CSS processor is considered to support a font format when it is capable of utilising the specified font format in layout and rendering, and this format is not specified as a <string>", which is similar to the prose excluding an unknown -webkit pseudo-element for a supported selector.

[vitorroriz]

At https://www.w3.org/TR/css-conditional-5/#at-supports-ext, It is confusing for me to read:

Note: The allowed values for the font-format() function are the same as those for the format() function in the '@font-face' src descriptor.

Given that at @font-face src we accept <string> for legacy reasons.