Show Selection State In SideBar

In the design for iPad session at 19:45 an example of the SideBar on both iPad and macOS is shown.

This example shows the current selected row in the SideBar having a default selection state (accent color background on iPad and depth on macOS) which seems to be displayed to the user appropriately on both platforms.

Does anyone know how to implement this default form of selection state when using Sidebar?
Show Selection State In SideBar
 
 
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