Both answers are "translation" which is the same as up/down/left/right shifting.
Refer to the diagram below to see how the reflections combine to form this shifting. A composition of two reflections always leads to a translation whenever the mirror lines are parallel. The direction of the shifting is perpendicular to the parallel lines. If the mirror lines intersected, then we'd have a rotation instead.
I used GeoGebra to create the diagram.