UPDATE: From the NX documentation leak there's a screenshot which shows the Sleep Mode.
They look like what we have seen in the past, so brings some validity to the data that comes with the leak.
In the end the sidebar isn't for multitasking, but just the latest game news of the suspended game.
Although in the leak a quick menu was mentioned:
| The Switch features a Quick Menu. Press and hold the HOME Button for at least one second to display the Quick Settings screen on top of all other screens, including the HOME Menu and any applications. Unlike the 3DS, the active software will not be suspended when this menu is invoked |

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Nintendo showed how fast the system returned to gameplay thanks to its Sleep Mode during their experience day.
The screen captured had three rectangle snaps at the left bar. I thought back then it was a multitasking bar... but since the Switch has no apps (no Browser or Netflix), now I'm not so sure what it is? Maybe it's just to switch games, since it only does games.











