By default, ncdump output shows the structure of file metadata, but not performance-related characteristics, such as which format is used, whether variables are compressed, or what chunking configurations are afor netCDF-4 variables. To see this information displayed as if it were stored in special attribute values (with names beginning with "_"), use the "-s" option to ncdump.
The special attributes are named `_ChunkSizes', `_DeflateLevel', `_Endianness', `_Fletcher32', `_Format', `_NoFill', `_Shuffle', and `_Storage'. For details, see the ncdump man page.
The ncgen utility also knows about these special attributes, so they can be changed in CDL and run through ncgen to set them for a netCDF file without programming.