window-prev-buffers

window-prev-buffers is a built-in function in `C source code'.

(window-prev-buffers &optional WINDOW)

Return buffers previously shown in WINDOW.
WINDOW must be a live window and defaults to the selected one.

The return value is a list of elements (BUFFER WINDOW-START POS),
where BUFFER is a buffer, WINDOW-START is the start position of the
window for that buffer, and POS is a window-specific point value.