This control should only be used in your mobile templates. It defines the zones and their names that are made available to blocks when you configure a page.
Note that when you add multiple blocks to a zone, there will be a space between them. This comes from the default spacing on a StackLayout which is
10. If you want to remove the gap, simply add a
Spacing="0"property to your zone and all the blocks within will touch.
The name of the zone that will be used on the page details page when deciding where to place a block.
<Rock:Zone ZoneName="Main" />