On graphical displays, each Emacs window normally has narrow fringes on the left and right edges. The fringes are used to display symbols that provide information about the text in the window. You can type M-x fringe-mode to disable the fringes, or modify their width. This command affects fringes in all frames; to modify fringes on the selected frame only, use M-x set-fringe-style.
The most common use of the fringes is to indicate a continuation line (see Continuation Lines). When one line of text is split into multiple screen lines, the left fringe shows a curving arrow for each screen line except the first, indicating that “this is not the real beginning”. The right fringe shows a curving arrow for each screen line except the last, indicating that “this is not the real end”. If the line's direction is right-to-left (see Bidirectional Editing), the meanings of the curving arrows in the fringes are swapped.
The fringes indicate line truncation with short horizontal arrows meaning “there's more text on this line which is scrolled horizontally out of view”. Clicking the mouse on one of the arrows scrolls the display horizontally in the direction of the arrow.
The fringes can also indicate other things, such as buffer boundaries (see Displaying Boundaries), and where a program you are debugging is executing (see Debuggers).
The fringe is also used for drawing the cursor, if the current line
is exactly as wide as the window and point is at the end of the line.
To disable this, change the variable
nil; this causes Emacs
to continue or truncate lines that are exactly as wide as the window.