framep-on-display

framep-on-display is a compiled Lisp function in `frame.el'.

(framep-on-display &optional TERMINAL)

Return the type of frames on TERMINAL.
TERMINAL may be a terminal id, a display name or a frame. If it
is a frame, its type is returned. If TERMINAL is omitted or nil,
it defaults to the selected frame's terminal device. All frames
on a given display are of the same type.