From the manual System Actions section:
Set layout scale
Set the scale (or zoom) of an entire layout. This scales all the layers in the layout, taking in to account their scale rate property.
Set the scale (or zoom) of an entire layer, taking in to account its scale rate property.
Set scale rate
Set the scale rate property of a layer, which affects how quickly it scales (if at all).
When creating an action, you'll find them in the Layers & transforms group of system actions.