Here is a list of all documented files with brief descriptions:

src
app.cpp	The application type: the parser itself
argv.cpp	Recovery of the original command line on Windows
config.cpp	Reading and writing configuration files
config_fwd.cpp	Declarations for configuration-file readers and writers
encoding.cpp	Conversion between narrow and wide character encodings
error.cpp	The exception hierarchy thrown by the library
extra_validators.cpp	The heavier validators: type checks, set membership, and unit parsing
formatter.cpp	Definitions for the default help formatter
formatter_fwd.cpp	Declarations for the help formatters
option.cpp	The option type: one command-line option and everything set on it
split.cpp	Decomposition of command-line arguments and name specifications
string_tools.cpp	Low-level string manipulation shared across the library
timer.cpp	Small wall-clock timing helpers
type_tools.cpp	Type classification and string conversion
validators.cpp	The validator type and the built-in validators
version.cpp	Compile-time version information for the cli11 library