NXQ GFX LETTERBOX

From Quake Wiki

Shows that the engine supports the "r_letterbox" console variable, set to values in the range 0-100 this restricts the view vertically (and turns off sbar and crosshair), value is a 0-100 percentage of how much to constrict the view, <=0 = normal view height, 25 = 75% of normal view height, 50 = 50%, 75 = 25%, >=100 = no view.