scrollDown

Scrolls the active scroll region down by one line (SD, CSI 1 T).

Only cells within the active horizontal margins move, exposing blank cells at the top of the region. Scrollback is not consumed. The cursor position is preserved.

Scrolls the active region down by count lines, capped at its height. Non-positive counts are ignored. Preserves the cursor position and uses the same horizontal-margin rules as scrollDown, without consuming history. Work is bounded by the grid dimensions, not the supplied count.