describe-face is an interactive compiled Lisp function in `
It is bound to <menu-bar> <help-menu> <describe> <describe-face>.
(describe-face FACE &optional FRAME)
Display the properties of face FACE on FRAME.
Interactively, FACE defaults to the faces of the character after point
and FRAME defaults to the selected frame.
If the optional argument FRAME is given, report on face FACE in that frame.
If FRAME is t, report on the defaults for face FACE (for new frames).
If FRAME is omitted or nil, use the selected frame.