If you use the wheel of a mouse, this value determines the number of lines to scroll for each wheel movement. Note that if this number exceeds the number of visible lines, it will be ignored and the wheel movement will be handled as a page up/ down movement.
Os defnyddiwch olwyn llygoden, penna' r werth hon nifer y llinellau i sgrolio am bob symudiad o' r olwyn. Noder os yw' r rhif yma' n fwy na' r nifer o linellau yn y golwg, fe' i anwybyddir ac fe gaiff symudiad yr olwyn ei drin fel symudiad tudalen i fyny/ i lawr.