left = 1 right = see description [This control collides with save cursor [variant]]
Set Left and Right Margin
If right is not specified, 0 or bigger than the number of the right-most column, it is adjusted to the number of the right-most column.
if left is right of the right-most column, adjust it to the right-most column.
If left < right set the left and right column of the scroll region according to left and right and move the cursor to the top-left cell of the display (when in cursor origin mode is set to the top-left cell of the scroll region).
🛈 xterm only interprets this control when left and right margin is set. In this case it completely replaces save cursor [variant] which is not available in that mode.