Would be nice to have an even more compact csv-esque version of jsonb that knew how to store arrays of objects with the same keys in compressible column-major format, omitting the repeated keys (and even value types if possible), like a transposed csv file with a first column of headers + type info. And the ability to embed arrays of object encoded that way into arbitrary jsonb structures, as long as all the objects have the same keys and (simple enough) value types. Or is that what the (different?) Postgres jsonb format does?