x-display-monitor-attributes-list

x-display-monitor-attributes-list is a built-in function in `C source code'.

(x-display-monitor-attributes-list &optional TERMINAL)

Return a list of physical monitor attributes on the X display TERMINAL.

The optional argument TERMINAL specifies which display to ask about.
TERMINAL should be a terminal object, a frame or a display name (a string).
If omitted or nil, that stands for the selected frame's display.

In addition to the standard attribute keys listed in
`display-monitor-attributes-list', the following keys are contained in
the attributes:

source -- String describing the source from which multi-monitor
information is obtained, one of "Gdk", "XRandr",
"Xinerama", or "fallback"

Internal use only, use `display-monitor-attributes-list' instead.