What happens when pressing either L1 or R1 when located on the Home Screen of the PlayStation 4?

When located on the main Home Screen for the PlayStation 4, I’ve noticed that pressing either L1 or R1 on the DualShock 4 remote appears to perform some kind of action related to the menu. I’m totally blind, so can’t easily tell what happens when either of these buttons are pressed – would somebody be able to explain which menu/function is activated when either of these buttons are pressed on the Home Screen?