When a line is exactly as wide as the window, Emacs displays the cursor in the right fringe instead of using two lines. Different bitmaps are used to represent the cursor in the fringe depending on the current buffer’s cursor type.
If this is non-nil, lines exactly as wide as the window (not
counting the final newline character) are not continued. Instead,
when point is at the end of the line, the cursor appears in the right
fringe.
This variable specifies the mapping from logical cursor type to the
actual fringe bitmaps displayed in the right fringe. The value is an
alist where each element has the form (cursor-type
. bitmap), which means to use the fringe bitmap bitmap to
display cursors of type cursor-type.
Each cursor-type should be one of box, hollow,
bar, hbar, or hollow-small. The first four have
the same meanings as in the cursor-type frame parameter
(see Cursor Parameters). The hollow-small type is used
instead of hollow when the normal hollow-rectangle
bitmap is too tall to fit on a specific display line.
Each bitmap should be a symbol specifying the fringe bitmap to be displayed for that logical cursor type. See Fringe Bitmaps.
When fringe-cursor-alist has a buffer-local value, and there is
no bitmap defined for a cursor type, the corresponding value from the
default value of fringes-indicator-alist is used.