bug#54156: [External] : bug#54156: 28.0.91; set-face-attribute with a nil FRAME doesn't change the default

[Drew Adams]

> > The fact that we handle nil as 'unspecified' in the case of the color
> > is for compatibility with Emacs 20.  In Emacs 21 and later, a color
> > cannot be nil.  This is well-documented: a color must be a string or
> > 'unspecified'.  I don't think we want to resurrect that old
> > convention of nil; it's just that Damien and others will have to get
> > used to not using nil for a color.
> 
> Makes sense to me.  Then I guess there's nothing more to do in this bug
> report, and I'm closing it.

Too bad.