About the :distant-foreground face attribute

[Chong Yidong]

What is the purpose of this face attribute, newly introduced for 24.4?
It seems to be unused in Emacs itself.  Is there a concrete example of
this being needed in external packages or themes?

First of all, the name :distant-foreground is not intuitive.  What does
"distant" mean in this context?

Also, this feature has one ugly consequence.  Previously, the `default'
face must have all its face attributes specified, but now its
:distant-foreground face is unspecified.

Besides that, the implementation seems rather incomplete.  The Customize
interface, `modify-face', `face-spec-reset-face', and other parts of
Emacs haven't been updated for the existence of this face attribute.
It's unclear what functions like `face-foreground' should now do if
there's a :distant-foreground.

This all sounds like an invitation for more bugs.  In my opinion, this
feature is a bad idea.