Something is definitely wrong there: the cols/lines values in that
file seem correct, but the values shown in the tooltip when I drag the
bottom right corner of the frame to resize it are approximately half
that (41x11 in this case).

> (2) Now split the single window via C-x 3, evaluate (window--dump-frame)
>     again and post the new contents of the *window-frame-dump* buffer.
>     And please also post a png of the frame at that time.
>