Node:Argp Help Filter Keys, Up:Argp Help Filtering
The following special values may be passed to an argp help filter function as the first argument in addition to key values for user options. They specify which help text the text argument contains:
ARGP_KEY_HELP_PRE_DOC
ARGP_KEY_HELP_POST_DOC
ARGP_KEY_HELP_HEADER
ARGP_KEY_HELP_EXTRA
ARGP_KEY_HELP_DUP_ARGS_NOTE
ARGP_KEY_HELP_ARGS_DOC
args_doc
field from the argp parser. See Argp Parsers.