File format for dig_cats and cats files

# I have looked through g.help and all of the manuals I have for information
# on the file forat of dig_cats and cats files. If someone could point me in
# the right direction I would appreciate it.

File formats are not published as they tend to change frequently. GRASS
does however guarantee that the libraries used to retrieve data from the
files will remain much more constant. To ensure a long life for your
programs please use the extensive GRASS programming library.