Added in 2.7

/linemarker [-rsN] [window] |on|off]

Changes unread line marker ettings for a window.

If no window is defined, current window is used.

Switches

-r - Reset unread marker line position on [window].
-sN - If N = 0, enables the small unread line marker, if N = 1, disables the small unread line marker.

Parameters
[window] - Window to edit.
[on|off] - Enables or disabled unread line marker for all windows, unless [Window] is defined.