A service may have multiple layouts. For example, when an app has multiple product offerings (all you eat vs. limited content) or several user types (children vs. adults, country or region-specific users, etc.).
For example, service has specific layouts linked to both product and user type:

A layout represents the app Browse screen as a user would see it.
A layout consists of layout sections. A layout section chooses the style for the banners it contains. Each section contains (or links to) a banner group.
A layout page structure:

Layout section consists of:
Banner group id [mandatory]
Banner group id is an ID of a banner group you would like to show in the layout section
Style [mandatory]
It is how the content will be rendered in a layout section
Link type [optional] if added, it creates the “See all” button on the Browse screen for this layout section to expand it on a separate screen. It can open anything that is linked - a single release or artist, banner group, release group or series, etc.
Link value [optional] id of the linked content you would like to be opened on a separate screen