Thanks . Got it .

Content Fragments in a Private folder not getting published 

Thanks Mahesh but not sure where to add p.facets= true. If you go to /assets.html/content/dam and click on the filter -> asset type , u will be able to select one category and perform a search . Similar navigation do in Brand Portal , u can further drill down .

Is it possible to achive Nested Asset Search( faceted search ) in AEM 6.5.6 like brand portal Example , Type can be drilled down further based on mimetypes  based on - /libs/dam/content/predicates/omnisearch/mimetypes