cursor face

[Drew Adams]

I don't see any index entry for the `cursor' face in the Elisp manual.

I haven't yet found any mention of the `cursor' face in the manual by
searching and browsing, either, but perhaps it is there. I did find a
statement in node Color Parameters that frame parameter `cursor-color' is
equivalent to the :background attribute of the `cursor' face. (It would be
good to state that also at the place where the `cursor' face is described,
if it ever is.)

Question:

The `cursor' face is equivalent to the value of frame parameter
`cursor-color' - but for which frame? Or is face `cursor' somehow a
frame-local face? Frame parameters are frame-local variables, but I didn't
think that there was such a thing as a frame-local face. Is there?

I have the frame parameter `cursor-color' set to "Yellow" for
special-display frames, but "Red" for the default-frame-alist. If there is
no such thing as a frame-local face, then I would expect that the
:background of face `cursor' would correspond to the `cursor-color'
parameter for the default-frame-alist.

However, if I do `M-x customize-face cursor', no matter which frame or
buffer I am in when I do it, I get a customize buffer that shows me the
`cursor' face with background "Yellow" (not "Red").

When I show, in buffer Customize, the Lisp expression that defines face
`cursor', I see this: ((t (:background "Yellow"))). Why is the value for
`special-display-frame-alist' ("Yellow") what is used, not that for
`default-frame-alist'?

If I customize the value of the face background, changing from "Yellow" to
"Green", and click set for session but not save for future, I see no change
in any existing frame or in any frame created thereafter. Is that right?

Is there a bug here somewhere? Several bugs? What am I missing?