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For new development consider using /uPortal/api/v4.3/dlm/layout.json instead.
[GET] /uPortal/api/v4
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-3/dlm/layout.json) (uPortal 4.3+)
This provides your whole layout with folder (aka tab) structures and everything including regions, favorites, favorite collections, portlet publishing parameters, and certain UI information (are impersonating, can add tab, etc.).
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