Here is a list of all namespaces with brief descriptions:

[detail level 12345]

Ncxx14
Ndetail
NGU_VDBPointToolsInternal
Nhoudini_utils
Nllvm
Nnanovdb
Nio
NInternal	Internal functions for compressed read/write of a NanoVDB GridHandle into a stream
Nopenvdb
Nv10_0
Nio
Ninternal
Nmath
Npcg
Ninternal
Ninternal
Nmat3_internal
Ntypes_internal
Npoints
Nattribute_traits
Nfuture	A container for ABI=5 to help ease introduction of upcoming features
Nindex
Npoint_attribute_internal
Ninternal
Npoint_move_internal
Npoint_rasterize_internal
Nstatistics_internal
Ntransfer_internal
Ntree
Nleafmgr
Niter
Ncompression
Ntools
Ncomposite
Nds
Ngridop
Nlocal_util
Nlstrack
Nmorphology
Npoisson
Nvalxform
NScheme
Nutil
Nlogging
Nax
Nast
Ntokens
Ncodegen
Ncodegen_internal
Nmath
Nopenvdb_houdini
Nnode_info_text	Namespace to hold functionality for registering info text callbacks. Whenever getNodeSpecificInfoText() is called, the default info text is added to MMB output unless a valid callback has been registered for the grid type
NOSN
Npyopenvdb
Nstd
Nunittest_util