Function: font-face-attributes

Return a plist of face attributes generated by FONT.
FONT is a font name, a font-spec, a font-entity, or a font-object.
The return value is a list of the form

(:family FAMILY :height HEIGHT :weight WEIGHT :slant SLANT :width WIDTH)

where FAMILY, HEIGHT, WEIGHT, SLANT, and WIDTH are face attribute values
compatible with `set-face-attribute'. Some of these key-attribute pairs
may be omitted from the list if they are not specified by FONT.

The optional argument FRAME specifies the frame that the face attributes
are to be displayed on. If omitted, the selected frame is used. (fn FONT &optional FRAME)