A query that accepts any other query as base64 encoded string.
GET /_search { "query" : { "wrapper": { "query" : "eyJ0ZXJtIiA6IHsgInVzZXIiIDogIktpbWNoeSIgfX0=" } } }
This query is more useful in the context of the Java high-level REST client or transport client to also accept queries as json formatted string. In these cases queries can be specified as a json or yaml formatted string or as a query builder (which is a available in the Java high-level REST client).