Here are the data structures with brief descriptions:

Ccelprm	Celestial transformation parameters
Cdisprm	Distortion parameters
Cdpkey	Store for `DPja` and `DQia` keyvalues
Cfitskey	Keyword/value information
Cfitskeyid	Keyword indexing
Clinprm	Linear transformation parameters
Cprjprm	Projection parameters
Cpscard	Store for `PSi_ma` keyrecords
Cpvcard	Store for `PVi_ma` keyrecords
Cspcprm	Spectral transformation parameters
Cspxprm	Spectral variables and their derivatives
Ctabprm	Tabular transformation parameters
Cwcserr	Error message handling
Cwcsprm	Coordinate transformation parameters
Cwtbarr	Extraction of coordinate lookup tables from BINTABLE